Extreme PO4 Consumption?
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Old 04-13-2015, 09:02 AM   #1
Malakian
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Extreme PO4 Consumption?


I am having some trouble with twisted leafs on my AR, and GSA on some plants and the drift wood. I am dosing dry ferts (CSM+B,KNO3,KH2PO4,MgSO4,CaSO4, and K2SO4) directly to the tank EI method.
Co2 at 50-60ppm (no fish/shrimp/snails. Ph drop from 7.5-5.9. Drop checker yellow.) Aqua soil substrate, 2x54w t5ho at 35-45 par at substrate.

No3: 25ppm
Fe: 1.0ppm
PO4: Trying to keep at 2-3 ppm, but keeps bottoming out.
GH:7
KH:3
PH:5.97 when max co2, 7.23 before the co2 goes back on. Base PH of water after 24hr de-gas 7.49.

Co2 comes in via ceramic diffuser which is then placed directly under a powerhead. There is about 12x turnover, and good circular flow.
Co2 comes on 2 hours before lights on, and off 30 min before lights. BPS way to fast too count. Have a PH controller to check PH, don't use it for controlling Co2 as I have not been able to get stable co2 levels that way (drifting kh)

Yesterday morning I added KH2PO4 until my test read 5ppm (calibrated) and KNO3 to 50ppm (added a little too much, wanted about 30ppm). Measured No3,Fe, abnd PO4 this morning. PO4 0ppm. No3 25ppm.

Can the plants really be using this much PO4? Or does aqua soil absorb/take up PO4 as well?

How much should I keep dosing, seeing i'm having trouble with GSA? Just try to keep it at 2-3ppm with daily dosing maybe, but then I'm afraid the Fe will become unavailable?

Bump; May add my plants are growing ridiculously fast and pearling very well. I trimmed my plants, and 5-6 hours later I could barley see where I cut my Heteranthera zosterifolia, new small leafs already. Never had growth like this Never used aqua soil and Co2 this high either though. It will be a challenge I guess, when I need to dial down the Co2 to about 30-40 ppm for livestock. I am also using 18lbs tank in about a month with current diffusion method, so gets kinda annoying to keep filling the tanks too. Just wanted to make sure the plants got a good start, and try to eliminate the co2 as the problem if things occurred, as it always seems to be the culprit.

Bump 2nd: Come to think off, since my plants are growing so fast, maybe I need to up my micros too? Seeing my AR is getting some twisted leafes (both AR "mini", and AR "Pink"), and 3-4 leafs on a stem or two on my hygrophila siamensis "53B". Not even close to the AR twisting though, which is more or less every stem. Any ideas would be appreciated.
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Old 04-13-2015, 10:13 AM   #2
lee739
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You are well outside the normal envelope I suspect, I run CO2 about 20ppm, with medium lighting 7hr/d, and my NO3 drops by about 2-3ppm/48hr, PO4 about 0.7ppm over same. Not sure how much NO3/PO4 is added by fish feeding though....
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Old 04-13-2015, 10:23 AM   #3
Malakian
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Yeah, I guess so. But still the uptakes seem a bit extreme to be just the plants? I was a little fast on the No3 reading, its more like 35-40ppm. So it has decreased 10-15ppm in 24 hours, or probably more since i'm in the middle of the nitrite cycle which is adding some No3 as well. But without dosing it wouldn't go over 10ppm No3, and I've read at Barr Report that some plants really show there full potential at about 30ppm No3. So i'm trying to target that and keep about a 1:10 ratio to PO4.

I'm guessing its the aqua soil though. Since it is high CEC after all. And in the 2 first weeks I had to dose pretty amazing amounts of GH booster and Sodium Bicarbonate to stabilize the KH and GH at where I wanted it. Bumped up the PO4 to 5ppm again, and I'll recheck tomorrow.
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Old 04-13-2015, 12:32 PM   #4
Christophe
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I have a similar setup to you and have noticed the same thing with PO4. I put in 2 ppm every other day to keep the level up. I find that my system is also very consumptive of potassium, pinholes in AR leaves. I find that I don't have a problem maintaining NO3 at 20ppm or so, but PO4 and K are things I have to consistently work at to maintain.
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Old 04-13-2015, 12:47 PM   #5
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When you mention nutrient's dosed per EI are you adding the CSM+B on day after Macro nutrient's ?
I ask only because some report that the Iron and phosphate can precipitate out of solution if CSM+B and macro PO4 are mixed together and dosed at same time.
Is said to be why macro-micro package from say Aquariumfertilzer.com does not include PO4.
I do not fully grasp the mechanisim's by which this might happen, but thought I might mention it for consideration.
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Old 04-13-2015, 12:51 PM   #6
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Yeah, I am aware of that. Thanks for the heads up though. I have been dosing macros and micros every other day until I noticed the GSA and PO4 reaching 0. I have now been dosing PO4 everyday for 3 days, and other macro every other.
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Old 04-14-2015, 04:55 AM   #7
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I think you are over concerned about dosing phosphates. If you don't have enough in the water, double the amount you dose each time. I routinely double my KH2PO4 dosages from what the EI tables call for, in order to avoid green spot algae on the glass. It works very well for me, and always has. Also, there is no reason to keep any specific ratio between nitrates and phosphates. The ratio that seems to work well is a lot closer to 3-1 nitrates to phosphates than 10-1.

It looks like you may have high light, considering that you are getting a lot of pearling. With high light, and the fast plant growth that causes, you probably do need to increase your dosage of all of the fertilizers. Remember, excess fertilizers, even phosphates, don't cause algae in a planted aquarium.
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Old 04-14-2015, 08:16 AM   #8
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Quote:
Originally Posted by Hoppy View Post
I think you are over concerned about dosing phosphates. If you don't have enough in the water, double the amount you dose each time. I routinely double my KH2PO4 dosages from what the EI tables call for, in order to avoid green spot algae on the glass. It works very well for me, and always has. Also, there is no reason to keep any specific ratio between nitrates and phosphates. The ratio that seems to work well is a lot closer to 3-1 nitrates to phosphates than 10-1.

It looks like you may have high light, considering that you are getting a lot of pearling. With high light, and the fast plant growth that causes, you probably do need to increase your dosage of all of the fertilizers. Remember, excess fertilizers, even phosphates, don't cause algae in a planted aquarium.
Thanks Hoppy! I thought Barr mentioned somewhere that phosphate was the only nutrient that would cause algae if abundant? Maybe I miss-read, or not from a trusted source at all just remember wrong, who knows.

I'll continue dosing PO4 until I can get some sort of balance. Or at least make it last until next dosing and double everything else. Ill do another PAR reading with my Apogee and see where we are at, I was more aiming for medium light than high. To much trimming
So even something like 20ppm PO4 would be ok?

I know you don't need to follow a ratio for the nutrients, but I just saw that most used about 1:10 ratio PO4/NO3, and I like being exact with the numbers/measurements and all, so just used that as a guideline for PO4 levels so I had something to go from.

We'll Ill be dammned. You know I mentioned the Co2 to always seem to be the culprit? Indirectly it is the problem for me too, even with the high ppm. Hoppy was right of course. Too high light. PAR meter read around 70-80 par at substrate and 250-300 par at surface of water. Ended up raising the lights another 12" before reaching 50-55 par at the substrate and 150-200 at the surface

Those 2x54w T5HO's with high quality individual reflector sure is some powerful lights.
Now it looks kinda weird with the canopy so high, so I'm wondering of adding some floaters. Does any body have experience with azolla caroliniana? Really like the look of it, but know little about it. Does it grow as good as other floaters, does it get easily tangled in other plants and become a noxious plant in the tank, like riccia?

Bump: Also added PO4 to 8ppm, NO3 at 30ppm, and K to 15ppm. Ill also add a double dose of CSM+B tomorrow.
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Old 04-14-2015, 09:47 AM   #9
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I find it hard to imagine the level of plant mass you have is consuming that much P (5ppm in 24 hrs). There may be something to the Aquasoil being new (I have no exp using it, so idk). However, I agree with Hoppy about doubling the dose. It works for me too controlling gsa. I keep mine closer to 10 than to 5. If I run it much under 5 gsa starts to appear.

Raising the light is always a good move to arrest algae problems before they get worse. But it doesnt necessarily mean you had to much for the tank - just that you had too much for the current fert/co2 levels...or plant mass. With your level of co2 and available ferts, 80 PAR is more than doable.

I have ridiculous PAR. Substrate level in my 75 gal -




Ive been running that light for about 5 months. It has actually made the tank easier to manage. Plants grow more compact and bushy, rather than racing to the surface. Pruning/shaping has become a lot easier. I only point this out because you said you dont like the canopy being up that high.

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Old 04-14-2015, 10:27 AM   #10
dzega
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same problem here. i need to dose massive amounts of po4. and im sure its not plants using it up. 24h after dose i read close to 0. its been absorbed by something. the tank is dirted. what i do is just dose as much as needed(wich is 3xEI i think). ive seen this problem reported on forums by other from time to time but no real explanation.

another weird thing about this tank is its PH is low for given KH. thats why i cant use dropchecker for co2 monitoring

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Old 04-14-2015, 10:29 AM   #11
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The tank is only been filled about 3 weeks now, so I guess its still settling in. Maybe I can lower the lights some more when I get things in balance. I too have noticed that the plants tend to become more compact and bushy with higher light, but it has always been algae growing to when I've had intense lighting. But seeing the thread about Tom Barr and him measuring ada tanks at 30-40 par at substrate, with still amazing compact, bushy plants. So it should still be doable.

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Quote:
Originally Posted by dzega View Post
same problem here. i need to dose massive amounts of po4. and im sure its not plants using it up. its been absorbed by something. the tank is dirted. what i do is just dose as much as needed(wich is 3xEI i think). ive seen this problem reported on forums by other from time to time but no real explanation
My guess its the High CEC in the aqua soil. Some nutrients/minerals it readily absorb, some not like No3. So PO4 might very well be one of which it is absorbing. Exactly how the "mechanism" of CEC and chemicals work, I do not know, but this my general understanding of it.
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Old 04-14-2015, 03:09 PM   #12
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Quote:
Originally Posted by Malakian View Post
So even something like 20ppm PO4 would be ok?
Levels that high will make it very difficult to keep trace metals soluble. Pretty much the inverse of your problem, which is clearly that something is soaking up the phosphates you are adding.

If you do dramatically increase your dosage just to increase phosphates a little, you should keep a very close eye on your levels. You may suddenly hit a point where the phosphate 'sponge' becomes saturated, and phosphate levels explode.
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Old 04-16-2015, 10:09 AM   #13
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Just wanted to give an update for future problem solvers, and thank you all for the help.

Algae has more or less stopped growing, still there but not seen any new growth. And my cycle is done, so I chucked in 15 amano's yesterday, and will probably add about 30-50 black sakura today (depending on how many I have the patience to catch). They should clean it up in a jiff ^^ Plants are still growing plenty fast for me, and still pearling
And it seems like the AR's has a lot less twisting, there is still some waving in some leafs, but nowhere near as bad as before.

I'm still doing 2x EI on everything, except i'm not dosing any KNO3 at the moment. NO3 stays at about 20ppm now after the nitrite bacteria caught up and with the lower ligth. And something (probably the ada) is still sucking PO4 like a sponge, 5ppm per day. So I'm going to add about 6ppm PO4 everyday until that stops. And dialed down the Co2 a tad, just for saftey measure on the shrimp. The ph drop is now about 1.3-1.4, instead of 1.5-1.6.

bump: Oh, and added a purigen bag to the filter, not that has anything to do with this. But its a change made none the less.
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Old 04-16-2015, 10:25 AM   #14
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Quote:
Originally Posted by Beefy View Post
Levels that high will make it very difficult to keep trace metals soluble. Pretty much the inverse of your problem, which is clearly that something is soaking up the phosphates you are adding.

If you do dramatically increase your dosage just to increase phosphates a little, you should keep a very close eye on your levels. You may suddenly hit a point where the phosphate 'sponge' becomes saturated, and phosphate levels explode.
Thanks for that, not that i'm going that high. Was just curios Ill keep an eye out for when it starts stabilizing. I'm not stopping my daily testing until things are settled and I know how much my plants are using of everything and I will dial it in from there, so I'll stay on top of it.
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Old 04-16-2015, 10:43 AM   #15
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Oh crap. I just remembered, I have montmorillonite clay (and red clay, if that matters) under the substrate. I don't know exactly how it does it, but it has some adsobring/absorbing or ion neutralizing (or something down that street, can't remember exactly :P ) cleaning properties. It has probably something to do with this. Added quite a bit too.

How I did not think of that before is beyond me. :O
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