Having trouble keeping phosphate up

[jsiegmund]

I have a bit of an issue getting the phosphate level in my tank to decent values and I want to understand why. I am using a drop test to monitor the values and although there is sometimes a hint of blue in the water, I can't get it to show a real blue color which it should be.

This seems to be the case since I switched to Akadama. I read these soils might take up some PO4 in the begin period, but I've got it for several months (4) now, and there's still nothing happening. At the moment, I'm dosing 6 ppm / week and just upped that to nearly 10 just to see what will happen.

Why change it at all? I think it's whats causing poor plant growth in my tank. Some plant species like pogostemon helferi and bacopa sp japan are struggling. Lower leaves are melting and algae are always present (BBA, hair, green spot). Of course there are other factors like CO2, nutrients and light but I do believe I have those under control, at least well enough. Other plant species are doing better (blyxa, enchinodorus tenellus, eleocharis parvula and others) so that leads me to think that stuff like light and CO2 is at least well enough.

So if I want to get PO4 up to something like 0.5 or 1, I just keep adding the dose until something happens, or are there other factors to take into account? I'm dosing a PO4 stock solution made with powder from a local supplier, I know pretty sure it's ok. One drop in my test solution and it turns blue almost instantly.

If it is the Akadama, from what I read the roots of the plants should be able to use still use it. Especially the pogostemon has thick roots which seem to be ankers more than meant for uptake. Could this be why it is doing a bad job taking in PO4? Just trying to find some reasonable explanations here

 

[Vivian Andrew]

I never tested for po4 but when it is less your tank will show some sign like GSA in leaf and glass, I added Eichhornia Diversifolia plant last month and start getting GSA Eichhornia Diversifolia leaves also started turning black which is a po4 issue so in my EI dosing i increased po4 within a week all came to normal, i make EI stock solution according to calculator i use my dosing is 1ppm and now i increased to 2ppm below are the sites i used to make my EI stock solution.

http://rota.la/

http://www.theaquatools.com/fertilization-calculator

Pogostemon helferi will melt if your PO4 is high, for lush growth you need to increase nitrogen and water flow and good lighting will keep it compact, and whenever you increase or decrease dosing you need to give a weeks time for seeing the changes.

 

[ceg4048]

or are there other factors to take into account?

Hello,
Yes, the other factor is that PO4 test kits cannot actually tell you how much PO4 is in the water. You should stop using test kits to measure nutrient levels and simply dose the required amount. You will save yourself a lot of trouble in the long run and will save money too.

Cheers,

 

[roadmaster]

Me think's that if one were to search out PO4 target range with something like EI dosing scheme , which assures non limiting macro/micro nutrient's , That one can fully appreciate what Clive is saying about test kit's.
If target range for particular nutrient was say 1.0 to 2.0 ppm, and my test kit indicated nothing after adding 6 to 10 ppm,then I would question the test kit's result's or the tester.

 

[jsiegmund]

Hello,
Yes, the other factor is that PO4 test kits cannot actually tell you how much PO4 is in the water. You should stop using test kits to measure nutrient levels and simply dose the required amount. You will save yourself a lot of trouble in the long run and will save money too.

Well before I had my akadama, those same tests worked fine. But fair enough, let's assume they don't. The "required amount" will still very much depend on how much the intake of plants is, correct? And if the soil is also absorbing, that amount would be even higher. So how to I find the required amount then? When I refer to the normal calculators, I'm already dosing too much and I really do not think lowering the dose is going to solve my growth/algae problems. So I'm not using the tests to measure as such but just to get an indication whether there is anything left in the water column.

 

[Rahms]

Well before I had my akadama, those same tests worked fine. But fair enough, let's assume they don't. The "required amount" will still very much depend on how much the intake of plants is, correct? And if the soil is also absorbing, that amount would be even higher. So how to I find the required amount then? When I refer to the normal calculators, I'm already dosing too much and I really do not think lowering the dose is going to solve my growth/algae problems. So I'm not using the tests to measure as such but just to get an indication whether there is anything left in the water column.

look at the EI tutorial. You dose excess and forget about it! much easier

 

[jsiegmund]

look at the EI tutorial. You dose excess and forget about it! much easier

That's the point: I am already doing that. I'm dosing even more than EI prescribes and still have deficiencies. So I tested to find out why and it turned out PO4 in my water column is zero, at least according to the tests.

 

[ceg4048]

Well before I had my akadama, those same tests worked fine.

Yes, but unfortunately, that was also an illusion. PO4 test kits only ever work as if they were a lottery. Just as frequently, the test kit reads a false high and the hobbyist, being paranoid about PO4 then restricts the dosage level. That's where the trouble starts. The low levels of PO4 causes the plants to suffer and this triggers algal blooms or causes other health issues. The hobbyist then blames the high PO4 reading for their troubles and this sets up a never ending cycle of problems. There is hardly such thing as dosing too much PO4, so straight away we can tell that this is leading down the wrong path.

As mentioned by Rahms and other posters, read the EI Tutorial and dose the amounts shown in the article based on your tank size or use the calculator in the link. Then forget about trying to micromanage the nutrient levels based on measurements.

Cheers,

 

[Jose]

If you dont want to listen to ceg jsiegmund, then you have to at the very least calibrate your test kit. You should forget about the test kits imo though. You are obviously being missguided by them at the moment.

 

[jsiegmund]

Okay, let's make it clear that I very much appreciate everyones input. Especially Clive's whom I regard as the expert given his track record on these forums. Let's also make it clear that I'm already dosing by EI. It's too easy to say all problems will just magically disappear when you just follow EI, that's not true as its success depends on more than just adding the right nutrients. There's flow, CO2, light, well you guys know it.

So whilst dosing via EI (NO3, PO4 and Ferrdrakon for micro's), I am still seeing deficiency problems and algae popping up. So one tries to eliminate probably causes. I have done so for CO2 (yellow drop checker, 1 point drop before lights on). I have done so for flow (upgraded to FX5 with spray bar). I have done so for lighting, etc. etc.

The only option I have got to check if my water column nutrients are ok are these tests. It's not like the plants are going to write my an e-mail to tell me what's wrong. So I have tested to see what the levels were and the PO4 surprised me because I expected it to turn blue which it didn't. So I googled around and found some stuff on Akadama absorbing PO4 which made me wonder whether this could the a problem or not. That was when I posted this question. So it's fine to tell me to dose EI, but perhaps we can focus a bit more on the original question instead.


PS: dosing according to EI would mean I drop my PO4 back to the level I had it on for months (2 ppm). I can do that, but I fail to see why that would suddenly make a difference when nothing else changed.

 

[ian_m]

then you have to at the very least calibrate your test kit

Calibration is irrelevant, you cannot use a hobby test kit to measure PO4 levels in tank water. As Clive has stated there are other substances present in tank water that will cause PO4 test kits to misread, generally grossly under read or read zero, despite PO4 being present. People see this low level from their kit and start chasing and worrying about something that is a non issue.

Overdosing PO4 is not an issue either. After a pump failure and dumping 1litre of double strength EI solution into my tank my PO4 level was 85ppm....nothing happened. No algae, no fish issues and more boringly no change in plants....

 

[Jose]

The only option I have got to check if my water column nutrients are ok are these tests. It's not like the plants are going to write my an e-mail to tell me what's wrong. So I have tested to see what the levels were and the PO4 surprised me because I expected it to turn blue which it didn't. So I googled around and found some stuff on Akadama absorbing PO4 which made me wonder whether this could the a problem or not. That was when I posted this question. So it's fine to tell me to dose EI, but perhaps we can focus a bit more on the original question instead.

If you run a test. If you prepare two solution of say 5 and 10/15 ppm phosphates in RO water and then test it. Your test kit should show two different colours. At least this way we can know your test kit is minmally working (not saying its appropriate). Then you can test your tank water. This way you wont get an exact ppm at all but you can know if you have some or no phosphates in the water. Not that this is gonna be of much help though.

 

[ian_m]

Then you can test your tank water.

Regardless of calibration, it will not read the correct PO4 level, due to other substances present in tank water. My bet is it will read zero....

This had been shown time and time again, dose tank using dry salts to certain ppm level. Wait a while, use hobby test kit to measure level....surprise surprise it doesn't agree with the ppm you have just dosed at...

 

[Rahms]

The only option I have got to check if my water column nutrients are ok are these tests. It's not like the plants are going to write my an e-mail to tell me what's wrong. So I have tested to see what the levels were and the PO4 surprised me because I expected it to turn blue which it didn't. So I googled around and found some stuff on Akadama absorbing PO4 which made me wonder whether this could the a problem or not. That was when I posted this question. So it's fine to tell me to dose EI, but perhaps we can focus a bit more on the original question instead.

I think the problem is that the test kits provide a way of "measuring" nutrients, so you're focusing on that, because you can't measure other stuff (or, you've got a positive result in case of CO2). You've got a bigger filter- therefore decided flow is solved. You've got a yellow drop checker- therefore decided CO2 is solved. Now you've looked at an unreliable test and concluded this is where your problem is, when in reality, having a big filter and a yellow drop checker doesn't mean your flow and CO2 is perfect. Where is the drop checker in your tank? You said its pogostemon helferi and lower parts of bacopa that are struggling- close to the substrate, which is where it's hardest to get good flow/distribution.

Some photos would probably help

 

[Jose]

Regardless of calibration, it will not read the correct PO4 level, due to other substances present in tank water. My bet is it will read zero....
This had been shown time and time again, dose tank using dry salts to certain ppm level. Wait a while, use hobby test kit to measure level....surprise surprise it doesn't agree with the ppm you have just dosed at...

If the kit is not able to read phosphates at all then youll find that out when you run the test mentioned before. It definately wont give a ppm, as you state ian m because of so many things but it can give a sense of having some or no phosphates at all if used correctly.

 

[jsiegmund]

I think the problem is that the test kits provide a way of "measuring" nutrients, so you're focusing on that, because you can't measure other stuff (or, you've got a positive result in case of CO2). You've got a bigger filter- therefore decided flow is solved. You've got a yellow drop checker- therefore decided CO2 is solved. Now you've looked at an unreliable test and concluded this is where your problem is, when in reality, having a big filter and a yellow drop checker doesn't mean your flow and CO2 is perfect. Where is the drop checker in your tank? You said its pogostemon helferi and lower parts of bacopa that are struggling- close to the substrate, which is where it's hardest to get good flow/distribution.

Some photos would probably help

You're making assumptions here. I am not saying I have CO2 solved; I am saying that based on a yellow drop checker and 1 point drop it is probably safe to say that it's not terrible. Same goes for flow, I'm not saying it's superb but it's not terrible either. The tablets for my corydoras float away when I place them in the area where the pogostemon is. So there definitely is flow.

So let me ask you guys a question. If all of the tests are rubbish and you have a tank running on EI which has some sort of problem, whatever that is. How do you solve it then? Just dose EI some more and wait for it to go away on it's own? I'd say you need to have some way to at least have an indication of something to improve. And when the obvious ones (CO2, flow) are ok, then what? Or do you recon that dosing EI is sufficient to rule out any issues with nutrients / water chemistry? I'm not criticizing here, just want to understand the reasoning.

Photo's:

 

[ian_m]

Seeing as EI is about 5-10 x what the plants actually need/use, lack of ferts won't be the issue.

On saying that we have seen people dosing levels that are way way out, in that they mixed their ferts wrong and dosed wrong giving virtually no fertz in the tank.

Also seen people roll their own EI mixes and doses, usually missing the cheapest ingredient, MgSO4 out as they have hard water so must have Mg in it so no need to use MgSO4. Wrong.

So in summary only leaves a CO2 issue or incorrect light levels. "Mechanical" defects in plants usually points to low/incorrect CO2.

Some people have reported some specialist aquatic soils leaching huge amounts of ammonia for the first couple or months, fatal for fish and damaging for plants and filter flora/fauna. Solved by daily water changes and/or use of Amquel+ (or equivalent).

 

[Jose]

EI normally does rule out all issues with nutrients yes as long as its done correctly and with all nutrients. That said, there are some cases where something with nutrients might not be right though. Like in your case of a soil adsorbing the nutrients (Im not saying its true but its a possibility), or also the case of very very hard water (this is another possibility). These cases are quite uncommon, yet CO2 cases are very very common and thats why its so easily misdiagnosed.

 

[roadmaster]

If dosing via EI which ensures Non limiting,(key word) and you have a problem, nutrient's or lack thereof are most often not going to be the problem.
This only leaves lighting, CO2 delivery,distribution, and or flow to help get the gas to lower regions for carpet type plants.
The gas want's to leave nearly as fast as it is entering and might very well be why suggestion of moving the drop checker around to different area's as well as lower, might be informative.(color may indicate not as much as hoped for nearer the bottom)
Course,,lowering the intensity and duration of the lighting would lower the demand for nutrient's as well as CO2 and this alone might bring relief assuming as you say the CO2 delivery/distribution is adequate.
If I spoon in or squirt in X ppm of a nutrient as per a dosing scheme, then I know the nutrient is there.
I do not worry bout the uptake rate of the plant's for the amount I added is non limiting.
If by some mechanisim the substrate adsorbed some as well,then plant root's will utilize it as well.
I can take comfort (trust) that the plant's will not need more for growth until next dose which happens to be in line with weekly water changes that most sign on for when they begin the hobby.

GAHHH! I'm too slow with my fat stubbyfingers to get message out before other's.

 

[jsiegmund]

Ok so I will give you a bit more info on what and how I dose and other details.

PO4 and NO3 I buy in powder form from a Dutch guy (I think he's on ukaps as well). It's KNO3 and KH2PO4 in pure form. I'm using RO water to create two stock solutions and use a dosing pump to daily dose the appropriate amount in my tank (happens just before lights on). For the rest of the nutrients, I use Ferrdrakon. Actually just finishing the last of it and then I'm switching to KramerDrak which is supposed to be even a bit better. But still, Ferrdrakon is also perceived as a very good source of nutrients for plants. That one is dosed after lights off, 6ml / day (= 42ml / week). Recommended is 25ml / week for a tank my size. I must admit that I haven't translated these values to EI and wouldn't exactly know how to do so.

My water change is once a week in the weekends, 40%. I'm using 50/50 tap vs RO, where my tap water is moderate (KH9 / GH7... measured with drop tests....). The akadama lowers the KH to 1, GH is normally around 8 - 9.

I'll move the drop checker closer to the bottom to see whether that matters.

Ferrdrakon consists of:

3,000 mg/l potassium, 1,000 mg/l iron, 750 mg/l magnesium, 400 mg/l manganese, 60 mg/l boron, 20 mg/l copper, 20 mg/l molybdenum, 20 mg/l zinc, 10 mg/l nickel, 10 mg/l cobalt, 4.6 mg/l iodide, EDTA, HEEDTA, DTPA, NTA, methyl paraben, ascorbic acid

Source: http://www.drak.de/en/freshwater/fertilizer/ferrdrakon.html