I recently bought some red plants for my 20 gallon long. I always hear that red plants, "need extra iron to stay red." If that is true, tell me if you think I'm already adding enough iron, if not how much more should I add? 3 times a weeks I add 1/16 teaspoons of plantex B and 1/32 teaspoons of Iron Chelate 11% DPTA. Other possible useful info,new plants LUDWIGIA sp 'red' and Ludwigia Repens Rubin, 30inch planted plus 7 hour photo period, pressurized CO2, carib sea floramax substrate capped with black sand.