Flourish shows that Flourish is 0.32% iron. So, if you want 1 ppm, or 1 mg/liter of iron in the tank, add 1/.0032 mg of Flourish per liter of water, or about 300 mg (.3 grams) of Flourish per liter, which is 300 ml of Flourish per liter of water. Would somebody check this to see if I made a decimal mistake?
FYI, I have developed a dry powdered form of Fe gluconate, same stuff as SeaChem Flourish Fe BTW.
It's just dry(shipping is 10X less) and lot cheaper.
Alan will be selling and I'll have the % Fe for you folks here in a week or so.
I am still planning to get something rather new and 100% absorbable by plants(they cannot use the gluconate nor ETDA, DTPH etc) and have found a highly super rich product that is ideal.
It's about 18% Fe.
The rest is a protein plants can take up diretcly and use as nitrogen source.