DrTim's AquaticsClear Up Natural Water Clarifier, Freshwate

For a fluval spec 3, do i need to use the whole bottle or can i just use half?

Does it create ammonia?

I forgot to shake the bottle...do I need to start over? Also, it left white residue spread all over the gravel is that normal?

Is it safe to use if I just used rapid fix ich repair on my tank ?