Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Remineralize with a GH booster that includes Ca & Mg in a ratio something close to 4:1. Seachem Equilibrium is one such material. It also contains potassium, a mineral that plants need.
Use something that supplies carbonates or bicarbonates. Baking soda or potassium bicarbonate are most commonly used in aquariums. If you buy a commercial product packaged for aquariums it is often sodium bicarbonate. Cheaper to just buy good 'ol baking soda in the grocery store.
Follow a fertilizer program to supply N, P, K, Ca, Mg, Fe, and other trace minerals.
Fish food can supply reasonable amounts of N, P and most traces.
GH booster supplies Ca and Mg.
I would fertilize with K and Fe for sure, and monitor the tank to see if the plants remove all the nitrogen from the fish food. If so, then also dose N, P and traces.