Craig.
That link tells me to put in 31mL of Flourish 2-4 times a week to maintain 0.5ppm of Fe.
I use just under 5ml 2 times a week as that is what is says on the container...
Not sure if that index is right or not.
When utilising the index for Flourish Fe it tells me to use 10mL whereas the container says 5mL
seems excessive again!
Nic.
Oops, sorry I didn't think on the iron as used to keeping macros and micro ferts separate. Potassium is the one I would check.
I generally aim to have tank readings at around 20 to 40ppm nitrates and potassium, 2ppm phosphate and 0.1 Fe. Which is roughly a factor of 10 from iron to phosphates to nitrates / potassium.
Looking at my spreadsheet I dose weekly 45ppm potassium, 3ppm phosphates and 0.25ppm iron and a bit of nitrates and micros. This is for CO2 injection (ph set at ~6.7) with medium lighting on a deep tank (quad t5ho). This is what works for my tank. I also use substrate ferts which do seem to help.
In reality my dosing varies depending on test results. Iron and copper never show up as much in test kits but I see browning in needle-like plants (foxtail, ambulia) if I "over-dose". Potassium on the test kit reads as 80 to 100ppm but if I lower this the hygro gets holes in lower leaves so stuck apparently over-dosing (or the test kit is just wrong).
As nitrates and phosphates are coming from fish waste and food, I find potassium will be the first to show as a deficiency with holes within lower leaves. Very rarely will I get such good plant growth that nitrates and phosphates come down close to 0 (usually after major filter cleans).
So to increase plant growth I have found increasing light intensity or period and CO2 helpful.
To deal with plant deficiency I have found increasing potassium to be the most helpful (plus substrate fert tabs for plants that are not good water column feeders). Increasing other ferts hasn't helped as much. But I'd check nitrates and phosphates as well.
I find shifting to dry ferts much, much cheaper and you can buy separately to control dosing. I used to dose the leaf zone and imo that is fine for low light tanks. For CO2 injection, I have found additional ferts dosing to be helpful. I have dosed higher in Fe (with other micros) up to 0.5% but found not much benefit. It may have actually been taking the copper a bit too high.
http://www.barrrepor...7-iron-toxicity