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#1
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Elodea suddenly "rots"--why?
Hello all,
I'm having a problem in my 29 gal. tank. The elodea, which normally grows very fast, between 1/4" and 3/4" per day, suddenly begins to disintegrate partway up the stalks. Symptoms are a lack of chlorophyll, the stem and leaves become translucent and all green goes away over the course of a few days. The growing tips of the plants remain green but with reduced growth, a very short inter-nodal length and the new leaves are "clamped" against the stalk. After a few days the stem comletely dies in the area where the problem began. Next the death spreads down the stalk toward the roots or base. Until this point the lower portions of the plant usually remain green and appear healthy. I can't seem to match these symptoms with an obvious deficiency, maybe I'm reading too much into the deficiency descriptions and it's something blindingly obvious? What adds to my confusion is that the other plants are doing VERY well. Several sword types have excellent color and are putting out new growth. The bronze crypts are growing well & spreading. The Hygrophila polysperma is doing better than it was recently, with better leaf size and growth rate. The corkscrew val. is still spreading via runners. The val. however is showing some yellowing on older leaves but they might just be old--I'm not sure if this is related or not. Java moss is "reclaming" sections of the tank at a decent rate. Any thoughts? Why is this one plant species rotting away? Tank parameters: Temp 74 deg. F Flourite substrate with minor amount of gravel & clay present lots of mulm in substrate. pH 7.0 KH = 2 deg. (this is adjusted with baking soda during water changes, tap water tests between 0 and 1 deg) GH = 4 deg. Ammonia = 0 NO2 = 0 NO3 = ? somewhere between 2.5 and 10 ppm depending on the test used. This value is problematic because the two tests (liquid only reagents vs. powder reagent) both seem to indicate a clear value. Perhaps I should take the "middle" value on the chart and say it's 5 ppm? I know this value is important but the tests are frustrating. Water out of the tap shows 0 for both tests. Nitrate is added via KNO3 in homemade PMDD. Phosphates = ~.25 ppm. Iron = .1 ppm. Iron is added via trace element mix. (Flourish trace) Light is a whopping 3.7 watts/gal via a dual compact flourescent fixture. CO2 has only been running on the tank for 2 days via DIY method. The problem described with the elodea began before the CO2 was added. I'm not sure how much exactly is there. The "chart" or calculator suggests 6 ppm. (bubble rate is currently 1 bubble about every 4-6 seconds) Bubbles get injected into the input of a powerhead and come out in a cloud of tiny bubbles. Some of the gas never dissolves as the bubbles float to the surface. Any general observations would be very much appreciated and any insight into the main question: Why the heck is my elodea disintegrating? Thanks, Lee |
#2
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Elodea suddenly "rots"--why?
I would have to say that the water temp is to warm for elodea. It is
a plant that does best in colder water, around the mid 60s. Even though it is widely sold by many LFS, it naturally grows in slow moving water that is cool. Someone else may have more insight on the problem. The above is from my observations. Good luck. "Lee Clemmer" wrote in message ... Hello all, I'm having a problem in my 29 gal. tank. The elodea, which normally grows very fast, between 1/4" and 3/4" per day, suddenly begins to disintegrate partway up the stalks. Symptoms are a lack of chlorophyll, the stem and leaves become translucent and all green goes away over the course of a few days. The growing tips of the plants remain green but with reduced growth, a very short inter-nodal length and the new leaves are "clamped" against the stalk. After a few days the stem comletely dies in the area where the problem began. Next the death spreads down the stalk toward the roots or base. Until this point the lower portions of the plant usually remain green and appear healthy. I can't seem to match these symptoms with an obvious deficiency, maybe I'm reading too much into the deficiency descriptions and it's something blindingly obvious? What adds to my confusion is that the other plants are doing VERY well. Several sword types have excellent color and are putting out new growth. The bronze crypts are growing well & spreading. The Hygrophila polysperma is doing better than it was recently, with better leaf size and growth rate. The corkscrew val. is still spreading via runners. The val. however is showing some yellowing on older leaves but they might just be old--I'm not sure if this is related or not. Java moss is "reclaming" sections of the tank at a decent rate. Any thoughts? Why is this one plant species rotting away? Tank parameters: Temp 74 deg. F Flourite substrate with minor amount of gravel & clay present lots of mulm in substrate. pH 7.0 KH = 2 deg. (this is adjusted with baking soda during water changes, tap water tests between 0 and 1 deg) GH = 4 deg. Ammonia = 0 NO2 = 0 NO3 = ? somewhere between 2.5 and 10 ppm depending on the test used. This value is problematic because the two tests (liquid only reagents vs. powder reagent) both seem to indicate a clear value. Perhaps I should take the "middle" value on the chart and say it's 5 ppm? I know this value is important but the tests are frustrating. Water out of the tap shows 0 for both tests. Nitrate is added via KNO3 in homemade PMDD. Phosphates = ~.25 ppm. Iron = .1 ppm. Iron is added via trace element mix. (Flourish trace) Light is a whopping 3.7 watts/gal via a dual compact flourescent fixture. CO2 has only been running on the tank for 2 days via DIY method. The problem described with the elodea began before the CO2 was added. I'm not sure how much exactly is there. The "chart" or calculator suggests 6 ppm. (bubble rate is currently 1 bubble about every 4-6 seconds) Bubbles get injected into the input of a powerhead and come out in a cloud of tiny bubbles. Some of the gas never dissolves as the bubbles float to the surface. Any general observations would be very much appreciated and any insight into the main question: Why the heck is my elodea disintegrating? Thanks, Lee |
#3
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Elodea suddenly "rots"--why?
Leigh,
Thanks for your reply. Yikes! That's too way too much light to have on a tank without CO2 injection. You need to get your CO2 levels up. That's what we're working on now with the DIY setup. Relevant points. Yes it's a lot of light I guess my casual response is that TMTOWTDI! When I had lower wattage fixtures everyone here insisted that I needed MORE light! I certainly know that you can have too much of a good thing, and that this light level is rather high. I have/had been using Flourish Excel as a supplemental source of carbon. I never took the time to set up the CO2 system although it was rather easy to do. The tank did well with a different group of plants with low light and no CO2--no surprise there. The plants were growing well, as was the Egeria, without any CO2 addition and with minimal additions of Excel. They grow/grew well for months. Algae problems that were easily remedied came and went depending on changes in fertilization. There's probably more algae there than you or some of the crew would accept, but it's not much. Recently the algae problem was "fuzz" that covered some leaves, a bit like razor stubble a few days old. This is going away with the addition of more NO3. The snails are cleaning up as well. Almost all the plants were PEARLING without the addition of CO2. The high light conditions no doubt had the plants sucking as much CO2 out of the water as possible, possibly leaving very little. Some of the plants might have the ability to use carbon from carbonate, as some algae can. Tom or George mentioned this recently in another thread. I can't speak to this issue in detail but the tank constantly needs the addition of bicarbonate to maintain any measurable KH. How long has this tank been set up with that lighting? And how do you keep the temperature at 74 degrees with that much light over the tank? It's been at least 6 months. The room temp is 70 degrees F. The light is separated from the tank by a 3/8" piece of glass, and the front and back of the top of the tank are open along the length of the tank; 3/4" slits all the way across, allowing heat to escape. It's not a closed hood. I just checked the temp again and 4" deep into the tank it's showing 73 deg. I guess there's just not that much of a heating effect with this setup. The temp hasn't changed since that plant was introduced, so the original question remains, why is the stuff rotting now? Thanks again, Lee |
#4
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Elodea suddenly "rots"--why?
I would have to say that the water temp is to warm for elodea. It is
a plant that does best in colder water, around the mid 60s. Even though it is widely sold by many LFS, it naturally grows in slow moving water that is cool. Someone else may have more insight on the problem. The above is from my observations. Thanks, Now that's an interesting thought, Leigh mentioned it as well. One variable here that has changed is the *location* of the heater in the tank. I moved it over to the Egeria's side of the tank a while ago. It only comes on at night, but perhaps the *local* temerature in the tank near the plants in question gets too hot. The heater may have been creating a hot spot in that area of the tank, as circulation was not great. The powerhead injecting the CO2 has added a lot more circulation but it may be too late to save this group of plants. Lee |
#5
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Elodea suddenly "rots"--why?
David Whittaker on the APD suggests that this is due to a critical shortage
of calcium and that the plant does not like the level of sodium vs. calcium. This sounds reasonable since I have adjusted carbonate hardness with sodium bicarbonate rather than calcium carbonate. A good source of calcium carbonate that is inexpensive should be easy to find. Lee |
#6
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Quote:
I'm keeping a photo-log: Daphnia vs. Green Water |
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