six piranhas

How do i know the levels of iron in my tank?Flourish iron does not really say how often to use.What can happen if overdosed?New to this forum.
80 gl. tank
6ix red belly piranhas
12 plants
swords
wisteria
moneywort
ludwigia
I use other flourish products.Should i follow the amounts givin,no matter the # of plants in the tank?

trenac

If you are dosing a micro nutrient, you should be suppling your tank with enough iron. If you want to make sure, dose 5mm for every 10 gallons once a week. There is really no good way to test for iron. Over dosing iron can cause algae problems.