Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
KNO3 from Aquarium Fertilizer (I have not looked at GLA product line, but I would assume it is the same) is agriculture grade, provides a fertilizer value of:
This is the official way fertilizer is rated in the USA. The first number is nitrogen, the second if phosphorus, the third is potassium. (actually it is a little bit different, but the concept is right) These are % by weight.
So, KNO3 is...
13+44 = 47.
that leaves 53% by weight oxygen.
There are no additives, no fillers, no binders.