My amazon sword has been showing sings of iron deficiency over the last month. I've increased my dose of Flourish Iron but unless I does about 5ml three times a week the leaves start going yellow. Is this a normal intake? I have 70% eco-complete which I thought would be more than enough for a sword. Of course, I have plenty other plants too. Ever since I added compressed CO2 I seem to be losing >1ppm of NO3 and PO4 every day.