Hello! I have a lot of houseplants at home, and I'm trying out the semi-hydro on three of them (marble pothos and tradescantia). Looking at fertilizers, it looks like they all come in HUGE bottles for like $60! I'm looking for a smaller bottle, maybe under $20? Thinking of using only General Hydroponics FloraGro (the green one) for my houseplants. I don't need all three, do I? Any recs for other fertilizers on a budget? Thanks!!!!