I have a 10g with 4.5 wpg and co2, 20 gallon with 2.5 wpg and a 55 gallon with 2.75 wpg.
Filtration for the 10 and 20 are tetra tec 20-30 and for the 55 gallon I have a Rena XP3 and an AC110.
my 10 houses guppies, platties, mystery snails, ramshells and pond snails. They don't bother my plants because I feed them broccoli weekly.
My 20 gallon houses mated pair of angels, 2 Bolivian rams, striped raph and 2 featherfin syno.
The 55 houses 7 discus, 2 mated pair of angels, 1 common pleco, a bunch of tetras and 1 gold t-bar cichlid.