Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
My understanding of Flourite is that it has a reasonable cationic exchange capacity so it can hold fertilizers available for the plants, but does not have ferts in itself. The long list of ingredients is not so much a list of what is available to the plants, but the components of the flourite itself. (Like describing the china and paint on the plate instead of telling you that there is no food on the plate) Adding a source of ferts like Laterite for iron is OK, but you could also add slow release tablets under the substrate and water column dosing.
From any source these ferts will get into the substrate and be held, ready for the plants.