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#1
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Do i need magnesium??
Firstly some background
Im running a 160litre planted tank, pretty heavily planted. Pressurised co2 at about 25 ppm, 120 watts of lighting 10 hrs a day; 5hrs light, 2 dark, 5 light. Plants are growing ok but i think there is some problem with the take up of some nutrients. Im dosing as recommended by numerous sources as follows. Firstly, a rundown of my tapwater, im doing 50% water changes weekly on a saturday. Tap water Iron 0.017ppm Nitrate 40ppm Alkalinity as HCO3 289ppm Calcium 134ppm Magnesium 3.8ppm (*LOW??*) Potassium 4ppm Treating tapwater with Hagen Aqua Plus for chloramines. PH with co2 injection in my tank is about 7.2 Here is what i have been dosing.... 20ppm potassium sulphate once a week with water change 0.5 ppm potassium phosphate twice a week, on a tuesday and thursday No nitrate as yet, still high in my tank. 10ml Kent Freshwater Plant 2x a week on tuesday and thursday. Ive been dosing this for 4 weeks now and plants have been growing well but bba has started to appear on some of my slow growers. I bought a phosphate and iron test kit today and my tank is currently in the following state (its a monday night) Nitrates 20ppm Iron (chelated) .75ppm Phosphates 1ppm. I would have thought my phosphates would be lower and that this is probably what is causing the BBA. Im going to stop dosing this until my phosphates get a bit lower. This is my main priority; i want phosphates to be the limiting nutrient in my tank. Currently it seems to be something else. Ive also notices that some of my leaves are developing yellow edges and brown veins which i initialy thought to be due to iron deficiency. Turns out that this isnt the case (assuming a valid test kit) so i'm led to Magnesium (or lack thereof) preventing the uptake of the iron. QUESTIONS Is it more than likely that magnesium is what im missing?? If so, what ppm of magnesium do i need to aim for? IMAGES Some images may help What is the problem here - http://www.marktrueman.com/images/brownvein.jpg The veins of this plant are brown?? Any ideas??? http://www.marktrueman.com/images/irondef.jpg Is the yellow leaf iron/magnesium deficiency? (Excuse the black molly in the photo) And heres a recent pic of the tank if you are interested http://www.marktrueman.com/images/tank.jpg Thanks for your help Mark |
#2
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Do i need magnesium??
What is the problem here - http://www.marktrueman.com/images/brownvein.jpg
The veins of this plant are brown?? Any ideas??? I have exactly similar plant. New leaves generally like that. But it will change to dark green within few days. BTW what is that plant? -- Thank You Dominic http://www.dlink.org/aqua |
#3
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Do i need magnesium??
I think its some kind of Echinodorus, not sure which one, maybe "tricolor"
No ideas on the magnesium then?? Mark "Aqua" wrote in message ... What is the problem here - http://www.marktrueman.com/images/brownvein.jpg The veins of this plant are brown?? Any ideas??? I have exactly similar plant. New leaves generally like that. But it will change to dark green within few days. BTW what is that plant? -- Thank You Dominic http://www.dlink.org/aqua |
#4
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Do i need magnesium??
"Mark Trueman" wrote in message
... Firstly some background Im running a 160litre planted tank, pretty heavily planted. Pressurised co2 at about 25 ppm, 120 watts of lighting 10 hrs a day; 5hrs light, 2 dark, 5 light. Plants are growing ok but i think there is some problem with the take up of some nutrients. Im dosing as recommended by numerous sources as follows. Firstly, a rundown of my tapwater, im doing 50% water changes weekly on a saturday. There is no need to have a dark period in your tank. It disrupts the natural daily plant cycle and it doesn't help with algae. Tap water Iron 0.017ppm Nitrate 40ppm Alkalinity as HCO3 289ppm Calcium 134ppm Magnesium 3.8ppm (*LOW??*) I would add some Mg in this case. It might never be depleted at this level, but I believe it has to be balanced with the calcium, or the calcium might block the consumption of Mg. I'd aim for 50 ppm Mg. MgSO4 is cheap and easy to find. I have a lot of Ca but no measurable Mg in my tap water, and I add about 2 degrees worth of Mg every week. PH with co2 injection in my tank is about 7.2 According to my calculations, your KH as CaCO3 is 26 degrees, which would give you 49 ppm CO2 with that pH. If that's correct, it's a little high. Here is what i have been dosing.... 20ppm potassium sulphate once a week with water change 0.5 ppm potassium phosphate twice a week, on a tuesday and thursday No nitrate as yet, still high in my tank. 10ml Kent Freshwater Plant 2x a week on tuesday and thursday. Nitrates 20ppm Iron (chelated) .75ppm Phosphates 1ppm. I would have thought my phosphates would be lower and that this is probably what is causing the BBA. Im going to stop dosing this until my phosphates get a bit lower. This is my main priority; i want phosphates to be the limiting nutrient in my tank. Currently it seems to be something else. The PO4 is not what's causing your BBA. Stopping the addition of PO4 will just make it worse. You have to figure out what nutrients your plants are lacking. Because you're not adding KNO3 (and that's okay), you should add more K2SO4 to make up for the K in KNO3. I'm not sure if you meant that you were adding 20 ppm of K2SO4 or 20 ppm of K from K2SO4, but I would dose at least 25 ppm of K per week just to be on the safe side. It will be dangerous to have the PO4 be the limiting nutrient in your high-light tank. The nutrient that you want to be limiting is light. It is likely that the poor health of some of your plants and the appearance of BBA are connected. Address the deficiency symptoms and the algae will retreat. From your photos, it looks like it could be one of a number of trace deficiencies. Are those symptoms occuring on new leaves or old leaves? If new leaves are affected, it usually suggests a lack of traces. Old leaves suggests a lack of macros. I would increase the Kent supplement a little bit and see if that helps. But I would add some MgSO4 first. __ Alex pcalex (at) hotpop.com |
#5
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Do i need magnesium??
There is no need to have a dark period in your tank. It disrupts the
natural daily plant cycle and it doesn't help with algae. Funny you should say that, an hour before i even read your response i had removed the dark period from my tank. PH with co2 injection in my tank is about 7.2 According to my calculations, your KH as CaCO3 is 26 degrees, which would give you 49 ppm CO2 with that pH. If that's correct, it's a little high. I have conflicting readings, my water authority gives me that value of 289ppm (which i work out as 289/17.86=16.81dKH using the formulae on http://www.thekrib.com/Plants/CO2/ha...arryfrank.html) but when i test kh with a test kit from the tap it comes out at about 13 dKH which i believe is about 22 ppm co2. Id rather go with a test kit of my own water. Im only bubbling 40 bubbles a minute into my eheim so i cant see that i would be able to get 49ppm with that, even if my kh was 26. Im probably one of many who doesnt quite understand kh/gh. My kh test kit says 13 so thats what im going with!! Here is what i have been dosing.... 20ppm potassium sulphate once a week with water change 0.5 ppm potassium phosphate twice a week, on a tuesday and thursday No nitrate as yet, still high in my tank. 10ml Kent Freshwater Plant 2x a week on tuesday and thursday. Nitrates 20ppm Iron (chelated) .75ppm Phosphates 1ppm. I would have thought my phosphates would be lower and that this is probably what is causing the BBA. Im going to stop dosing this until my phosphates get a bit lower. This is my main priority; i want phosphates to be the limiting nutrient in my tank. Currently it seems to be something else. I'm not sure if you meant that you were adding 20 ppm of K2SO4 or 20 ppm of K from K2SO4, dosing enough k2so4 to put in 20ppm of K per week, i sometimes put a bit in mid week as well. Are those symptoms occuring on new leaves or old leaves? Its old leaves, so you suggest a possible lack of macros. I think most of my macros are in abundance, the only one i dont test is K and i add about 20ppm per week of that. You also say about increasing my trace mix dosage. Im worried about too much iron, my current dosage has my iron at about 1ppm currently which i think is a bit too high. Maybe this will decrease faster as i add mgso4; the trace+iron will be taken up by the plants at a faster rate, keeping the iron levels down. How much Mgso4 do i need to get to the 50ppm you mentioned? Those calculations throw me!! I think its about 14 tsp a week (using the krib pages) in my tank of 160 litres, maybe you could confirm this. Seems like a lot of mgs04. Thanks for your help Mark |
#6
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Do i need magnesium??
"Mark Trueman" wrote in message
... PH with co2 injection in my tank is about 7.2 According to my calculations, your KH as CaCO3 is 26 degrees, which would give you 49 ppm CO2 with that pH. If that's correct, it's a little high. I have conflicting readings, my water authority gives me that value of 289ppm (which i work out as 289/17.86=16.81dKH using the formulae on http://www.thekrib.com/Plants/CO2/ha...arryfrank.html) but when i test kh with a test kit from the tap it comes out at about 13 dKH which i believe is about 22 ppm co2. Id rather go with a test kit of my own water. Im only bubbling 40 bubbles a minute into my eheim so i cant see that i would be able to get 49ppm with that, even if my kh was 26. Im probably one of many who doesnt quite understand kh/gh. My kh test kit says 13 so thats what im going with!! Yeah, I kind of suspected that might not be right because it's unusually high. KH test kits measure alkalinity as CaCO3, not HCO3. The ratio of the atomic weights of CaCO3 and HCO3 is about 1.6, so the alkalinity in the published water analysis is really 473 ppm, or 26 degrees. But yes, I would go with the results of the KH test kit, as you're doing. Are those symptoms occuring on new leaves or old leaves? Its old leaves, so you suggest a possible lack of macros. I think most of my macros are in abundance, the only one i dont test is K and i add about 20ppm per week of that. Well, in that case, Chuck Gadd's nutrient deficiency article at http://www.csd.net/~cgadd/aqua/art_plant_nutrient.htm suggests it might be the magnesium as well. That's one more sign that your plants are lacking Mg. You also say about increasing my trace mix dosage. Im worried about too much iron, my current dosage has my iron at about 1ppm currently which i think is a bit too high. Maybe this will decrease faster as i add mgso4; the trace+iron will be taken up by the plants at a faster rate, keeping the iron levels down. The iron test kits are not really useful for determining how much iron is available to plants and it's unclear what kind of iron they are measuring. Other hobbyists keep Fe at 1.0 ppm without problems. I add about 0.7 ppm per week to my high-light tank, and it never measures very high. But if you say that it's the old leaves that are affected, try adding the Mg first before increasing the traces. And keep up that PO4. How much Mgso4 do i need to get to the 50ppm you mentioned? Those calculations throw me!! I think its about 14 tsp a week (using the krib pages) in my tank of 160 litres, maybe you could confirm this. Seems like a lot of mgs04. The quick way is to just add the dry MgSO4 gradually until your measured GH increases by 2 or 3 degrees. It's definitely not 14 tsp a week. For my 30-gal. tank, one mL (1/5 tsp) of dry MgSO4 by volume increases the GH by one degree. You could also use Chuck's nutrient dosage calculator at http://www.csd.net/~cgadd/aqua/art_p...osage_calc.htm to make an MgSO4 solution. __ Alex pcalex (at) hotpop.com |
#7
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Do i need magnesium??
Magnesium 3.8ppm (*LOW??*)
How did you calculate this Mg Level? -- Thank You Dominic http://www.dlink.org/aqua |
#8
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Do i need magnesium??
"Aqua" wrote in message ...
Magnesium 3.8ppm (*LOW??*) How did you calculate this Mg Level? Its what's on the report from my water people. I dont think you can get test kits easily for Mg can you?? |
#9
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Do i need magnesium??
You can subtract Ca from GH (normally Ca+Mg)...
Philippe "Mark Trueman" wrote in message om... | "Aqua" wrote in message ... | Magnesium 3.8ppm (*LOW??*) | | How did you calculate this Mg Level? | | Its what's on the report from my water people. I dont think you can | get test kits easily for Mg can you?? |
#10
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Do i need magnesium??
You can subtract Ca from GH (normally Ca+Mg)...
Sorry guys, How do you measure Ca? Do you have any test kit for Ca? -- Thank You Dominic http://www.dlink.org/aqua |
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