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UV steralizer
is it wise to run the UV steralizer 24 hours a day? assuming that you only
desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
Along these lines, I would like to know if anyone has diy ozone generator?
maybe big enough to use on swimming pool also. Any electronics techs out there with ideas? I am also a tech. As to you chris, why run it 24 hours, would eat the bulbs fast that way. And not do any better job. Best to check manufacturer's recommendations. Just my thoughts :) "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
The bulb life will go way down if you turn it off and on
Christopher wrote: is it wise to run the UV sterilizer 24 hours a day? assuming that you only desire a 99.9% sterilization rate you don't have to run the sterilizer that much (depending upon gph through the sterilizer and tank size). I've read: 9.2 * (tank size / gph through sterilizer) = hours a day UV sterilizer must be on to attain 99.9% sterilization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% sterilization or for 8 hours a day? |
UV steralizer
the manufacturer has no recommended run time
double helix 36W "James Thompson" wrote in message t... Along these lines, I would like to know if anyone has diy ozone generator? maybe big enough to use on swimming pool also. Any electronics techs out there with ideas? I am also a tech. As to you chris, why run it 24 hours, would eat the bulbs fast that way. And not do any better job. Best to check manufacturer's recommendations. Just my thoughts :) "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
is turning it on and off once a day that bad for it? I would think the fact
that I would be running it for 1/3 of the time would outweigh the shortening of life from the on/off cycles (I would just put it on a timer after all). "m.dekort" wrote in message ... The bulb life will go way down if you turn it off and on Christopher wrote: is it wise to run the UV sterilizer 24 hours a day? assuming that you only desire a 99.9% sterilization rate you don't have to run the sterilizer that much (depending upon gph through the sterilizer and tank size). I've read: 9.2 * (tank size / gph through sterilizer) = hours a day UV sterilizer must be on to attain 99.9% sterilization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% sterilization or for 8 hours a day? |
UV steralizer
http://www.aquasite.com/knowledge/ti..._reactor.shtml
"James Thompson" wrote in message t... Along these lines, I would like to know if anyone has diy ozone generator? maybe big enough to use on swimming pool also. Any electronics techs out there with ideas? I am also a tech. As to you chris, why run it 24 hours, would eat the bulbs fast that way. And not do any better job. Best to check manufacturer's recommendations. Just my thoughts :) "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
Is a $20 bulb every year really worth it? Run it 24 hours a day.
"Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
Actually, the 9.2 factor will give you 99.99 % throughput through the sterilizer. To get 99.9% throughput, the factor is 6.9. See http://www.wideopenwest.com/~brucege...ver/index.html for details. One strategy is to set the flow rate through the sterilizer so that one pass kills target organisms you wish to kill. If you set the flow rate slow enough that everything you want to kill is killed, then run your sterilizer long enough to "turnover" the tank water once or twice a day, and then shut the sterilizer off. Basically, the more slowly you put water through the sterilizer, the more UV exposure every bit of water passing through the sterilizer receives. If you have a 36 watt sterilizer with about a 3 inch diameter chamber for the water, and your flow rate is about 100 gallons per hour, then you are probably irradiating your water at about a 100 microwatt-seconds dose, which is enough to kill most bacteria, algae, and many protozoa. (This is only a crude estimate; I am working on developing some assessment tools on my website which will provide more specific advice..) If you are using a lower wattage sterilizer, or a lower diameter sterilizer, then your flow rate will need to be lower still to achieve the same dose. In the article I wrote cited above, I show that when you have run 99.9% of the water through the sterilizer at least one time, in actuality 99.2% of water has passed through 2 or more times, and 96.8% will have passed through the sterilizer 3 or more times! I recommend 6.9*(tank size in gallons)/(flow rate in gallons) to be your target turnover time. If your flow rate is chosen with some care, you need not run your sterilizer all the time. You will save bulb life by running your sterilizer through only one or two turn-over intervals per day. I hope you enjoy the article on turnover time; this is the first time I have published the web address. Remember that you can skip to the conclusion and get the formula to use. I am in process of collecting data for a suite of articles on the topic UV sterilizers. Be watching this news group or my web site; I am waiting on data from a manufacturer. -Bruce Geist "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
NETMAX alert. Grab this URL guy!
-Donald Bruce Geist wrote: Actually, the 9.2 factor will give you 99.99 % throughput through the sterilizer. To get 99.9% throughput, the factor is 6.9. See http://www.wideopenwest.com/~brucege...ver/index.html for details. One strategy is to set the flow rate through the sterilizer so that one pass kills target organisms you wish to kill. If you set the flow rate slow enough that everything you want to kill is killed, then run your sterilizer long enough to "turnover" the tank water once or twice a day, and then shut the sterilizer off. snip good stuff I hope you enjoy the article on turnover time; this is the first time I have published the web address. Remember that you can skip to the conclusion and get the formula to use. I am in process of collecting data for a suite of articles on the topic UV sterilizers. Be watching this news group or my web site; I am waiting on data from a manufacturer. -Bruce Geist -- "When you've lost your ability to laugh, you've lost your ability to think straight." -To Inherit the Wind |
UV steralizer
Thats a very detailed explanation, THANKS!
have a couple questions though: if the primary reason I'm using the steralizer is to kill algae spores so my tank stays clean is it smart to only have the steralizer running for X hours a day? Cant the spores be released and land and settle on the glass and leaves during the off period? My second question is how much life of the bulb is saved when you run it for 8 hours a day? I know that the turning on of the bulb takes away from bulb life, but would the fact that its only run for 1/3 of the time save bulb life in the long term? I am concerned since 36W PC florescents are $50 (not exactly cheap) "Bruce Geist" wrote in message ... Actually, the 9.2 factor will give you 99.99 % throughput through the sterilizer. To get 99.9% throughput, the factor is 6.9. See http://www.wideopenwest.com/~brucege...ver/index.html for details. One strategy is to set the flow rate through the sterilizer so that one pass kills target organisms you wish to kill. If you set the flow rate slow enough that everything you want to kill is killed, then run your sterilizer long enough to "turnover" the tank water once or twice a day, and then shut the sterilizer off. Basically, the more slowly you put water through the sterilizer, the more UV exposure every bit of water passing through the sterilizer receives. If you have a 36 watt sterilizer with about a 3 inch diameter chamber for the water, and your flow rate is about 100 gallons per hour, then you are probably irradiating your water at about a 100 microwatt-seconds dose, which is enough to kill most bacteria, algae, and many protozoa. (This is only a crude estimate; I am working on developing some assessment tools on my website which will provide more specific advice..) If you are using a lower wattage sterilizer, or a lower diameter sterilizer, then your flow rate will need to be lower still to achieve the same dose. In the article I wrote cited above, I show that when you have run 99.9% of the water through the sterilizer at least one time, in actuality 99.2% of water has passed through 2 or more times, and 96.8% will have passed through the sterilizer 3 or more times! I recommend 6.9*(tank size in gallons)/(flow rate in gallons) to be your target turnover time. If your flow rate is chosen with some care, you need not run your sterilizer all the time. You will save bulb life by running your sterilizer through only one or two turn-over intervals per day. I hope you enjoy the article on turnover time; this is the first time I have published the web address. Remember that you can skip to the conclusion and get the formula to use. I am in process of collecting data for a suite of articles on the topic UV sterilizers. Be watching this news group or my web site; I am waiting on data from a manufacturer. -Bruce Geist "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
Basically, you are only culling the population of algae spores and bacteria
to a level, presumably, that is more like an open stream or lake. All tank water is never sterile at any one moment in time, since algae and bacteria are constantly re-growing. To control a specific organism or class of organisms, use the lowest lethal dose for that organism or class of organism, meaning you turn your flow rate up so that water passing though is exposed to the right level of radiation, and no more. That way, you are killing algae at the quickest possible rate. The flow rate is effectively your control on the dosage you are delivering. So, if algae is your target, I'd turn your flow rate to about 200 gallons per hour. This will deliver (I am estimating here) about 50,000 micro watt-seconds / cm^2 of radiation to the water passing through your sterilizer. Here is the shaky part; I am not sure exactly what dose will kill all algae. So be aware, I am making a swag here. I do know that Chlorella Vulgaris, a kind of algae, is killed by 45,000 micro watt-seconds / cm^2 of UV. Therefore, I am recommending a flow rate that I believe will cause your 36 watt sterilizer to deliver the 50 K micro watt-seconds / cm^2 dosage. I do not actually have intensity data for your particular sterilizer, though I have requested it from the manufacturer (because I am doing some mathematical modeling for an article I am writing..) I have intensity data for a 30 and 64 watt UV set-up, so I am interpolating a result here. However, the dosage estimate is really an estimate! Sorry I cannot be more precise. Now its your choice whether to leave on the sterilizer or cycle it. I do not believe the statement that cycling a UV lamp shortens its life significantly. Maybe it does, but I find it hard to believe. In fact, the lamp manufacturer defines its useful life in terms of hours on, not number of cycles. If you leave the thing on all the time, the lamp will last about 6 months. If you use it only during the day, my expectation is that it will last a year. Since your target is algae, maybe its enough to sterilize when the algae is multiplying during your tank's lighted period. Do some experiments, and see if you perceive a difference in water quality and/or algae proliferation when cycling and not cycling. And then let me know what you conclude! I'd really like to know what your experience turns out to be... -Bruce http://www.wideopenwest.com/~brucegeist "Christopher" wrote in message rthlink.net... Thats a very detailed explanation, THANKS! have a couple questions though: if the primary reason I'm using the steralizer is to kill algae spores so my tank stays clean is it smart to only have the steralizer running for X hours a day? Cant the spores be released and land and settle on the glass and leaves during the off period? My second question is how much life of the bulb is saved when you run it for 8 hours a day? I know that the turning on of the bulb takes away from bulb life, but would the fact that its only run for 1/3 of the time save bulb life in the long term? I am concerned since 36W PC florescents are $50 (not exactly cheap) "Bruce Geist" wrote in message ... Actually, the 9.2 factor will give you 99.99 % throughput through the sterilizer. To get 99.9% throughput, the factor is 6.9. See http://www.wideopenwest.com/~brucege...ver/index.html for details. One strategy is to set the flow rate through the sterilizer so that one pass kills target organisms you wish to kill. If you set the flow rate slow enough that everything you want to kill is killed, then run your sterilizer long enough to "turnover" the tank water once or twice a day, and then shut the sterilizer off. Basically, the more slowly you put water through the sterilizer, the more UV exposure every bit of water passing through the sterilizer receives. If you have a 36 watt sterilizer with about a 3 inch diameter chamber for the water, and your flow rate is about 100 gallons per hour, then you are probably irradiating your water at about a 100 microwatt-seconds dose, which is enough to kill most bacteria, algae, and many protozoa. (This is only a crude estimate; I am working on developing some assessment tools on my website which will provide more specific advice..) If you are using a lower wattage sterilizer, or a lower diameter sterilizer, then your flow rate will need to be lower still to achieve the same dose. In the article I wrote cited above, I show that when you have run 99.9% of the water through the sterilizer at least one time, in actuality 99.2% of water has passed through 2 or more times, and 96.8% will have passed through the sterilizer 3 or more times! I recommend 6.9*(tank size in gallons)/(flow rate in gallons) to be your target turnover time. If your flow rate is chosen with some care, you need not run your sterilizer all the time. You will save bulb life by running your sterilizer through only one or two turn-over intervals per day. I hope you enjoy the article on turnover time; this is the first time I have published the web address. Remember that you can skip to the conclusion and get the formula to use. I am in process of collecting data for a suite of articles on the topic UV sterilizers. Be watching this news group or my web site; I am waiting on data from a manufacturer. -Bruce Geist "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
I noticed after I posted that Chlorella Vugaris, a kind of algae,
is actually killed with a dose of 22,000 micro-watt-seconds/cm^2. If you assume most all algae is killed with a 30,000 unit dose, you will in fact want to increase the flow rate on your sterilizer further, to 250 or 300 gallons per hour. -Bruce "Bruce Geist" wrote in message ... Basically, you are only culling the population of algae spores and bacteria to a level, presumably, that is more like an open stream or lake. All tank water is never sterile at any one moment in time, since algae and bacteria are constantly re-growing. To control a specific organism or class of organisms, use the lowest lethal dose for that organism or class of organism, meaning you turn your flow rate up so that water passing though is exposed to the right level of radiation, and no more. That way, you are killing algae at the quickest possible rate. The flow rate is effectively your control on the dosage you are delivering. So, if algae is your target, I'd turn your flow rate to about 200 gallons per hour. This will deliver (I am estimating here) about 50,000 micro watt-seconds / cm^2 of radiation to the water passing through your sterilizer. Here is the shaky part; I am not sure exactly what dose will kill all algae. So be aware, I am making a swag here. I do know that Chlorella Vulgaris, a kind of algae, is killed by 45,000 micro watt-seconds / cm^2 of UV. Therefore, I am recommending a flow rate that I believe will cause your 36 watt sterilizer to deliver the 50 K micro watt-seconds / cm^2 dosage. I do not actually have intensity data for your particular sterilizer, though I have requested it from the manufacturer (because I am doing some mathematical modeling for an article I am writing..) I have intensity data for a 30 and 64 watt UV set-up, so I am interpolating a result here. However, the dosage estimate is really an estimate! Sorry I cannot be more precise. Now its your choice whether to leave on the sterilizer or cycle it. I do not believe the statement that cycling a UV lamp shortens its life significantly. Maybe it does, but I find it hard to believe. In fact, the lamp manufacturer defines its useful life in terms of hours on, not number of cycles. If you leave the thing on all the time, the lamp will last about 6 months. If you use it only during the day, my expectation is that it will last a year. Since your target is algae, maybe its enough to sterilize when the algae is multiplying during your tank's lighted period. Do some experiments, and see if you perceive a difference in water quality and/or algae proliferation when cycling and not cycling. And then let me know what you conclude! I'd really like to know what your experience turns out to be... -Bruce http://www.wideopenwest.com/~brucegeist "Christopher" wrote in message rthlink.net... Thats a very detailed explanation, THANKS! have a couple questions though: if the primary reason I'm using the steralizer is to kill algae spores so my tank stays clean is it smart to only have the steralizer running for X hours a day? Cant the spores be released and land and settle on the glass and leaves during the off period? My second question is how much life of the bulb is saved when you run it for 8 hours a day? I know that the turning on of the bulb takes away from bulb life, but would the fact that its only run for 1/3 of the time save bulb life in the long term? I am concerned since 36W PC florescents are $50 (not exactly cheap) "Bruce Geist" wrote in message ... Actually, the 9.2 factor will give you 99.99 % throughput through the sterilizer. To get 99.9% throughput, the factor is 6.9. See http://www.wideopenwest.com/~brucege...ver/index.html for details. One strategy is to set the flow rate through the sterilizer so that one pass kills target organisms you wish to kill. If you set the flow rate slow enough that everything you want to kill is killed, then run your sterilizer long enough to "turnover" the tank water once or twice a day, and then shut the sterilizer off. Basically, the more slowly you put water through the sterilizer, the more UV exposure every bit of water passing through the sterilizer receives. If you have a 36 watt sterilizer with about a 3 inch diameter chamber for the water, and your flow rate is about 100 gallons per hour, then you are probably irradiating your water at about a 100 microwatt-seconds dose, which is enough to kill most bacteria, algae, and many protozoa. (This is only a crude estimate; I am working on developing some assessment tools on my website which will provide more specific advice..) If you are using a lower wattage sterilizer, or a lower diameter sterilizer, then your flow rate will need to be lower still to achieve the same dose. In the article I wrote cited above, I show that when you have run 99.9% of the water through the sterilizer at least one time, in actuality 99.2% of water has passed through 2 or more times, and 96.8% will have passed through the sterilizer 3 or more times! I recommend 6.9*(tank size in gallons)/(flow rate in gallons) to be your target turnover time. If your flow rate is chosen with some care, you need not run your sterilizer all the time. You will save bulb life by running your sterilizer through only one or two turn-over intervals per day. I hope you enjoy the article on turnover time; this is the first time I have published the web address. Remember that you can skip to the conclusion and get the formula to use. I am in process of collecting data for a suite of articles on the topic UV sterilizers. Be watching this news group or my web site; I am waiting on data from a manufacturer. -Bruce Geist "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
I am not certain at all about when algae will bloom, or when the best time
to kill algae would be. 24/7 sounds like a good, if slightly more expensive way to go, since you want to be sure. If you do do some experimenting, let me know what you find. As I said in the earlier post, I am convinced that you will kill the most algae by tuning your flow rate to deliver the correct kill dose for algae -- about 30,000 micro-watts -sec / cm^2, and no more or less, regardless of whether you leave your sterilizer on 24/7 or not. This will kill the most algae, because the flow rate is highest without being too high to do kill algae. For your sterilizer, I would say 250 to 300 gallons per hour is what you want to flow through the sterilizer. Good luck. BTW, I saw Leigh's post. In my opinion, Leigh is right, you will need to do all the other algae control measures that you see discussed in this (rec.aquaria.freshwater.plants) newsgroup. Maintain proper growth nutrients for higher plants, get algae eating fish, maintain water quality, etc. I use a sterilizer in my tank, but did not for the first couple of years that I had my tank up and running. With a sterilizer, I notice clearer water, and possibly slightly less algae buildup on the tank walls. (But I still have to do a significant weekly cleaning..) I have seen a reduction of surface scum, and a marked reduction in cyano bacteria (blue-green algae), a particularly nasty smelling algae. I used to get small colonies near my filter return and sometimes near the interface between gravel and glass. It never spread. (The small colonies seemed to occur regardless of my nitrate levels. I have seen insufficient nitrate levels blamed for cyano bacteria.) Now I see very little blue green algae in my tank. I am hoping I will never see Ick in my tank again, but at this point I make no declarations. We'll see. -Bruce "Christopher" wrote in message rthlink.net... the thing is if one dose doesn't kill the algae spores then the second dose probably will (since it would get another dose roughly every hour), and in the meantime it will be very weakened. How certain are you that algae release their spores into the water during the day? I know for most people it isn't a big deal but I don't like algae in my tank and for me...having a steralizer seriously retard the spread of algae is worth it. That way I can run the lights more than 8 hours a day and I don't have to spend an hour scraping the sides of the tank every other week. I might just leave it at that and run the steralizer 24/7 unless you are fairly certain that I can time it to the release of algae spores. Since the whole purpose of this purchase was to severely minimize the amount of work I have to put into the tank I want to have the maximum algae retardation possibile. "Bruce Geist" wrote in message ... I noticed after I posted that Chlorella Vugaris, a kind of algae, is actually killed with a dose of 22,000 micro-watt-seconds/cm^2. If you assume most all algae is killed with a 30,000 unit dose, you will in fact want to increase the flow rate on your sterilizer further, to 250 or 300 gallons per hour. -Bruce "Bruce Geist" wrote in message ... Basically, you are only culling the population of algae spores and bacteria to a level, presumably, that is more like an open stream or lake. All tank water is never sterile at any one moment in time, since algae and bacteria are constantly re-growing. To control a specific organism or class of organisms, use the lowest lethal dose for that organism or class of organism, meaning you turn your flow rate up so that water passing though is exposed to the right level of radiation, and no more. That way, you are killing algae at the quickest possible rate. The flow rate is effectively your control on the dosage you are delivering. So, if algae is your target, I'd turn your flow rate to about 200 gallons per hour. This will deliver (I am estimating here) about 50,000 micro watt-seconds / cm^2 of radiation to the water passing through your sterilizer. Here is the shaky part; I am not sure exactly what dose will kill all algae. So be aware, I am making a swag here. I do know that Chlorella Vulgaris, a kind of algae, is killed by 45,000 micro watt-seconds / cm^2 of UV. Therefore, I am recommending a flow rate that I believe will cause your 36 watt sterilizer to deliver the 50 K micro watt-seconds / cm^2 dosage. I do not actually have intensity data for your particular sterilizer, though I have requested it from the manufacturer (because I am doing some mathematical modeling for an article I am writing..) I have intensity data for a 30 and 64 watt UV set-up, so I am interpolating a result here. However, the dosage estimate is really an estimate! Sorry I cannot be more precise. Now its your choice whether to leave on the sterilizer or cycle it. I do not believe the statement that cycling a UV lamp shortens its life significantly. Maybe it does, but I find it hard to believe. In fact, the lamp manufacturer defines its useful life in terms of hours on, not number of cycles. If you leave the thing on all the time, the lamp will last about 6 months. If you use it only during the day, my expectation is that it will last a year. Since your target is algae, maybe its enough to sterilize when the algae is multiplying during your tank's lighted period. Do some experiments, and see if you perceive a difference in water quality and/or algae proliferation when cycling and not cycling. And then let me know what you conclude! I'd really like to know what your experience turns out to be... -Bruce http://www.wideopenwest.com/~brucegeist "Christopher" wrote in message rthlink.net... Thats a very detailed explanation, THANKS! have a couple questions though: if the primary reason I'm using the steralizer is to kill algae spores so my tank stays clean is it smart to only have the steralizer running for X hours a day? Cant the spores be released and land and settle on the glass and leaves during the off period? My second question is how much life of the bulb is saved when you run it for 8 hours a day? I know that the turning on of the bulb takes away from bulb life, but would the fact that its only run for 1/3 of the time save bulb life in the long term? I am concerned since 36W PC florescents are $50 (not exactly cheap) "Bruce Geist" wrote in message ... Actually, the 9.2 factor will give you 99.99 % throughput through the sterilizer. To get 99.9% throughput, the factor is 6.9. See http://www.wideopenwest.com/~brucege...ver/index.html for details. One strategy is to set the flow rate through the sterilizer so that one pass kills target organisms you wish to kill. If you set the flow rate slow enough that everything you want to kill is killed, then run your sterilizer long enough to "turnover" the tank water once or twice a day, and then shut the sterilizer off. Basically, the more slowly you put water through the sterilizer, the more UV exposure every bit of water passing through the sterilizer receives. If you have a 36 watt sterilizer with about a 3 inch diameter chamber for the water, and your flow rate is about 100 gallons per hour, then you are probably irradiating your water at about a 100 microwatt-seconds dose, which is enough to kill most bacteria, algae, and many protozoa. (This is only a crude estimate; I am working on developing some assessment tools on my website which will provide more specific advice..) If you are using a lower wattage sterilizer, or a lower diameter sterilizer, then your flow rate will need to be lower still to achieve the same dose. In the article I wrote cited above, I show that when you have run 99.9% of the water through the sterilizer at least one time, in actuality 99.2% of water has passed through 2 or more times, and 96.8% will have passed through the sterilizer 3 or more times! I recommend 6.9*(tank size in gallons)/(flow rate in gallons) to be your target turnover time. If your flow rate is chosen with some care, you need not run your sterilizer all the time. You will save bulb life by running your sterilizer through only one or two turn-over intervals per day. I hope you enjoy the article on turnover time; this is the first time I have published the web address. Remember that you can skip to the conclusion and get the formula to use. I am in process of collecting data for a suite of articles on the topic UV sterilizers. Be watching this news group or my web site; I am waiting on data from a manufacturer. -Bruce Geist "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
UV steralizer
I may be wrong, but I believe that only incandescent bulb life is shortened
by turning it off and on due to the surge of electricity passing through the filament. This surge weakens the filament by vaporizing pieces of the filament. During normal usage, samll pieces of the filament detatch and float freely in the bulb, but they are drawn back to the filament to settle on it. It is the vaporization of the small pieces of the filament that shortens the life of an incandescent bulb. I don't believe the same is true for any flourescing type lamp, but I don't know as much about those types. "Bruce Geist" wrote in message ... Basically, you are only culling the population of algae spores and bacteria to a level, presumably, that is more like an open stream or lake. All tank water is never sterile at any one moment in time, since algae and bacteria are constantly re-growing. To control a specific organism or class of organisms, use the lowest lethal dose for that organism or class of organism, meaning you turn your flow rate up so that water passing though is exposed to the right level of radiation, and no more. That way, you are killing algae at the quickest possible rate. The flow rate is effectively your control on the dosage you are delivering. So, if algae is your target, I'd turn your flow rate to about 200 gallons per hour. This will deliver (I am estimating here) about 50,000 micro watt-seconds / cm^2 of radiation to the water passing through your sterilizer. Here is the shaky part; I am not sure exactly what dose will kill all algae. So be aware, I am making a swag here. I do know that Chlorella Vulgaris, a kind of algae, is killed by 45,000 micro watt-seconds / cm^2 of UV. Therefore, I am recommending a flow rate that I believe will cause your 36 watt sterilizer to deliver the 50 K micro watt-seconds / cm^2 dosage. I do not actually have intensity data for your particular sterilizer, though I have requested it from the manufacturer (because I am doing some mathematical modeling for an article I am writing..) I have intensity data for a 30 and 64 watt UV set-up, so I am interpolating a result here. However, the dosage estimate is really an estimate! Sorry I cannot be more precise. Now its your choice whether to leave on the sterilizer or cycle it. I do not believe the statement that cycling a UV lamp shortens its life significantly. Maybe it does, but I find it hard to believe. In fact, the lamp manufacturer defines its useful life in terms of hours on, not number of cycles. If you leave the thing on all the time, the lamp will last about 6 months. If you use it only during the day, my expectation is that it will last a year. Since your target is algae, maybe its enough to sterilize when the algae is multiplying during your tank's lighted period. Do some experiments, and see if you perceive a difference in water quality and/or algae proliferation when cycling and not cycling. And then let me know what you conclude! I'd really like to know what your experience turns out to be... -Bruce http://www.wideopenwest.com/~brucegeist "Christopher" wrote in message rthlink.net... Thats a very detailed explanation, THANKS! have a couple questions though: if the primary reason I'm using the steralizer is to kill algae spores so my tank stays clean is it smart to only have the steralizer running for X hours a day? Cant the spores be released and land and settle on the glass and leaves during the off period? My second question is how much life of the bulb is saved when you run it for 8 hours a day? I know that the turning on of the bulb takes away from bulb life, but would the fact that its only run for 1/3 of the time save bulb life in the long term? I am concerned since 36W PC florescents are $50 (not exactly cheap) "Bruce Geist" wrote in message ... Actually, the 9.2 factor will give you 99.99 % throughput through the sterilizer. To get 99.9% throughput, the factor is 6.9. See http://www.wideopenwest.com/~brucege...ver/index.html for details. One strategy is to set the flow rate through the sterilizer so that one pass kills target organisms you wish to kill. If you set the flow rate slow enough that everything you want to kill is killed, then run your sterilizer long enough to "turnover" the tank water once or twice a day, and then shut the sterilizer off. Basically, the more slowly you put water through the sterilizer, the more UV exposure every bit of water passing through the sterilizer receives. If you have a 36 watt sterilizer with about a 3 inch diameter chamber for the water, and your flow rate is about 100 gallons per hour, then you are probably irradiating your water at about a 100 microwatt-seconds dose, which is enough to kill most bacteria, algae, and many protozoa. (This is only a crude estimate; I am working on developing some assessment tools on my website which will provide more specific advice..) If you are using a lower wattage sterilizer, or a lower diameter sterilizer, then your flow rate will need to be lower still to achieve the same dose. In the article I wrote cited above, I show that when you have run 99.9% of the water through the sterilizer at least one time, in actuality 99.2% of water has passed through 2 or more times, and 96.8% will have passed through the sterilizer 3 or more times! I recommend 6.9*(tank size in gallons)/(flow rate in gallons) to be your target turnover time. If your flow rate is chosen with some care, you need not run your sterilizer all the time. You will save bulb life by running your sterilizer through only one or two turn-over intervals per day. I hope you enjoy the article on turnover time; this is the first time I have published the web address. Remember that you can skip to the conclusion and get the formula to use. I am in process of collecting data for a suite of articles on the topic UV sterilizers. Be watching this news group or my web site; I am waiting on data from a manufacturer. -Bruce Geist "Christopher" wrote in message rthlink.net... is it wise to run the UV steralizer 24 hours a day? assuming that you only desire a 99.9% steralization rate you don't have to run the steralizer that much (depending upon gph through the steralizer and tank size). I've read: 9.2 * (tank size / gph through steralizer) = hours a day UV steralizer must be on to attain 99.9% steralization rate (assuming uniform mixing). This said my calculation is at most 7 hours a day, should I just run it for 8 hours a day and save my bulb life and power bill? Should I run it 24 hours a day to achieve 99.999% steralization or for 8 hours a day? |
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