Hi.

I've been trying to find specific numbers on suggested ppm's in planted tanks, but I can't seem to find anything....specific.

So far I've got:

NO3 : 1-5ppm
PO4 : 0,5-2ppm
K : 10-20ppm
Mg : 5-10ppm

Do we have other suggested targets?

What about using different sources for NO3 for instance?
NH4NO3
HNO3 etc.

Is there a more extensive list?

Nitrates should probably be more in the 10 - 20ppm range. 1 - 5 will get exhausted too quickly in a planted tank. I use KNO3 for nitrate.


NH4 shouldn't be added to a planted tank. It will induce algae. This site has a useful calculator...

Calculating dosages of fertilizer elements for a planted tank

Iron and calcium are two other important components. My site has a downloadable .xls calculator for fertilizers also, link here.

Fertilization

HNO3 is no good.
Nasty acid that will destroy KH.

NH4NO3 is bad due to high NH4, ammonia.

Ca(NO3)2 is not bad.

Soft water folks use this + K2SO4, MgSO4 and KH2PO4

Do not mess with Fe and trying to maintain some pre set level.
There is no way to relate it to the needed levels for plants.
This was discussed at length several years ago between myself and a hydrogeologist.

He dealt with inorganic sides of the issue, I, the biological plant side.

Regards,
Tom Barr

I typically shoot for a target of 20ppm NO3, if I go +/- 10ppm, I'm fine no matter what.

You can semi limit growth using less than 20ppm, not enough to cause issues with growth development, but enough to slow the growth down a little.

Regards,
Tom Barr

Ok, 20 just seems high to me.
ack, All this calculating ppm's is driving me crazy.
how many percent No3 in KNO3, divided by this, times that, equals something else.. lol.

10-20 is fine.
20 is just the max amount that is non limiting.

This is not high as far fish health, you really do not see any issues with fish till you hit 100+ppm's and even then, with warmer water species, not until 200.

NO3 is not really toxic.
Folks have little idea how much toxic "is".
And that's the problem.

So they associate over conservative fearful risk that are not real.

Like most things folks do not know much about, they assume it's bad and are fearful of it.


Regards,
Tom Barr

thanks for the replies.

now several places, in books, etc. I've seen a NO3:PO4 ratio of 5:1

now 20ppm NO3 vs. 1ppm PO4 is nooooot quite 5:1

What gives?

The ratio of nitrate to phosphate isn't important. If you are going to use the "Redfield ratio", do it with nitrogen and phosphorous, but nothing I have seen shows any benefit to holding to that ratio anyway. I am pretty laid back about dosing phosphates too. If I have GSA annoying me I double the phosphate dosing to see if that helps. Sometimes it does.