I have a 29g with a 40 gallon sponge filter and a Fluval C4 hob filter. I do weekly 40-50% water changes and gravel vac each time. Right now I have 7 cardinal tetras, 6 lemon tetras, 2 Celebes rainbows, a horseface loach which I plan on either rehoming or donating to my lfs, and an oto, but I...