Turbo snails are cleaning machines. You only need 1 for every 25 gallons or so. With the rest of the cleanup crew, it's probably better to start small and add more later if you need them. Too many people start new tanks and follow the "1 hermit crab per gallon" rule they see online (usually from someone selling cleanup crews :-o ) or buy a package with way too many critters, only to see half of them die a few months later when the initial algae blooms subside and there isn't enough food to sustain them.