So i have a 20 gallon tank with about 2.7 watts per gallon of lighting. No C02, just using excel daily. Plants are doing fine, and algae is staying in check.
My question is this. About a week ago i started EI dosing. I am dosing about 1.8 ppm of nitrates daily for 6 days (7th day no dosing and 50% water change), and about .45 ppm of phosphates daily, about 2ml of iron daily, and potasium is added via nitrate and phosphate mix.
My question is this. I have been testing the water daily, and have found that each day my phosphate level does not go higher than .25 ppm. Nitrate after 6 days has gotten to about 5ppm.
It seems as if phosphate is being taken up faster than nitrate. My question is should i increase my phosphate dosing? Also, should i try to aim for 10 ppm nitrate or am i fine at 5ppm.
My tank is medium stocked as of right now, and i have a medium load of fish.
Last edited by mooch28; 07-13-2009 at 03:18 PM.
First off, you should probably calibrate your test kits if you haven't yet. I don't trust mine to do much more than indicate the presence of a chemical otherwise.
How do the plants look? Are they healthy? Relatively algae free? If so, it's not necessary to mess with a working system.
If your test kits are accurate, I'd say leave the phosphate alone and increase your nitrate; they're on the low side. I'd suggest aiming for at least 10ppm, but not being afraid to dose for 20-30ppm if that's what it takes.
Plants are healthy. As for the phosphate test kit, i have not calibrated it, nor do i know how accurate it is. I am using a AP test kit, if that means anything.....
As for nitrates, why should i increase it? If my tank shows 5 ppm nitrates after a week, does that not mean they are not taking it all in?
What lights do you have to get the 54 watts, and is that a 20L or 20H - is it 12 inches or 16 inches high? You might have more light than Excel can provide adequate carbon for, if those are T5HO lights.
The plants will use up nitrates and phosphates depending on how fast they are growing, and the light intensity plus the amount of carbon available to the plants will be most important in determining how fast they grow.
You know, maybe it's just me, but I've found that nitrates won't go below 5ppm in any of my tanks with complete starvation. Maybe they'd get there eventually, but the concentration in the water must not be high enough for efficient uptake. I find deficiencies show at this level, and things turn a wonderful yellow color.
Personally, I'd say if you have a working system that's outside the norm, go with it. Better yet, study it, find out why it works, and tell us all about it. Accidents make for great inventions.
On a side thought, I've considered making am iwugami tank (10g or something small) starved from nitrogen temporarily with little dioramas like this (warning, bloody art involving mangled miniature sculptures of people)