aquarium fertilizer

kopite · 06-14-2010, 07:43 PM

So, I was going to make PMDD, but couldn't find a chelated trace mix, but I found a ready mixed powder fertilizer that has a chelated mix in it. Here's a list of the ingredients 14% Nitrate Nitrogen, 6% P2O5, 13% K2O, 11% Ca, 1.44% Mg, 5.72% Sulphur, .01% boron, 0.001% chelated Cu, 0.03% chelated Fe, 0.01% chelated Mn, 0.002% Mo, and 0.014% chelated Zn. There's also 0.01% vitamin B1. The instructions say to put a tablespoon into 4 liters of water, but it seems to me that PMDD is more concentrated.

My first question is, is this okay to use in place of PMDD? There aren't any ammonia nitrates and it seems to have all the elements of PMDD.

Second, should I make the mixture a little less dilute if its okay to use?

ZeroSystem · 06-15-2010, 01:55 AM

Alright, I'll admit, I don't know what PMDD is.. But I somehow just know that this is the perfect question for Jay! Hopefully he'll swing by soon with some of his super-plant-guru-advice.

kopite · 06-15-2010, 08:37 AM

PMDD

mix with water to make a 1/2 liter solution,

1 tablespoon chelated trace mix
1 tablespoon MgSO4+7H2O
2 tablespoons K2SO4
1 tablespoon KNO3

Jay · 06-19-2010, 02:40 PM

I am not really sure what you mean by “chelated mix”. PMDD is an old acronym going back to the Sears-Collins days of experimenting with nutrients for planted aquariums. Now days we know that while much of their work was valid and accurate, they were in error about the use of phosphates PO4.
Many serious plant folks use dry fert mixes, me included. The important thing is to know why and then develop a program of adding nutrients required by your tank and plants. Dry mix nutrients give you very accurate control.

I use KNO3 to a weekly target of 30 ppm. 10 ppm three times a week (Nitrate)

I use KH2PO4 to a weekly target of 6 ppm. 2 ppm three times a week (Phosphate)

I get enough Potassium K from the Potassium Nitrate and Mono Potassium Phosphate

I use a Custom Mix of Ca, Mg, electrolytes and minerals at water change to keep my KH strong
These numbers are based on moderately high light and CO2 injected tanks.

For the important micro nutrients I use the great dry mix “Plantx-B”. I chunk in a little chleated iron. Keep in mind you cannot dose iron and PO4 at the same time. The iron will precipitate out and make a mess.

You can buy a pound of each for a total of $20 or so, enough to last over a year for 100 gal of water. Let me know if you need a source.

Jay