Hi all! I have a planted 20 gal acrylic tank. I regularly check the levels (nitrites, nitrates, chlorine, Ph, etc) and all are good. I have 7 neon tetras, 2 "tequila sunrise" guppies, 2 glofish, 2 yellow mystery snails and 1 or 2 baby mystery snails. I really would like to add more fish but...