Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Fish food is a pretty good source of most nutrients, for a low tech tank.
It is low in Fe, K and Ca.
Water changes should take care of the Ca, as long as the GH is at least 3 German degrees of hardness.
When I started with plants, very low tech, the first deficiencies I found were K and Fe.
So I also added C (Excel).
As I improved the lighting and reduced the fish load I found the plants also needed all the other nutrients, and higher doses of C, K and Fe.