pitabread

I've been having issues with a white precipitate forming on the surface of the water for quite some time now. I'm also having what appears to be calcium deficiencies.

Right now I'm dosing using the EI method. It's a 48 gallon tank and I dose 1/2 tsp of KNO3 and 1/8 tsp of KPO4 every other day. And on the other days, I dose 1/8 tsp of chelated trace mix.

I've read that potassium and iron can react and precipiate, which is why I dose the two chemicals on opposite days. The precipitate I'm getting mainly occurs after I dose the KNO3 and KPO4. It seems to gradually build through the week until I do a 50% at the end of the week. Then the whole thing begins again.

It's been awhile since I've tested my tap water, but in the past it's been very soft (GH/KH of 3-4 from what I remember). Starting this week, I'm going to use Seachem Equilibrium to attempt to bolster the water's mineral content. I've also been adding 1/2 cap of Seachem Flourish with the trace mix since it apparently contains calcium and magnesium.

Any thoughts on this?