[QUOTE=Hoppy]It isn't iron that causes red leaves. Generally those plants that produce red leaves do so with high light intensity and good, complete fertilizing. I think you should try to measure your CO2 level by taking a tank sample, degassing it for several hours, measuring the PH of that sample and comparing it to the tank PH. If the difference is 0.7, you have 15-20 ppm, if it is 1.0 you have 30-40 ppm, and if it is 1.3 you have 60-80 ppm. So, a 1.0 difference should be the goal.[/QUOTE
I did ,and the degassed sample had a ph of 8.1 compare to the tank's ph of 7.0 so with the difference of 1.1 I am getting over 30ppm.The red plants do get a lot of light,so may be I should hold off on adding more iron?
Thank for your reply Hoppy.