However, aquaponic systems are routinely deficient in a few nutrients – primarily potassium, calcium, and iron. we routinely address the potassium and calcium deficiencies by buffering (raising) our system’s ph with compounds based on those elements.. Well, dr rakcocy of university of the virgin islands (uvi) who is an advocate to fe-dtpa, recommends dosing 2 mg/liter (7.58 mg/gal) every 3 weeks. that would also depend on the percentage of iron content in the product that you are using. aqualron dtpa chelated iron comes with 10% iron..
