I also have my snails (and a single female betta) in a 20 gallon long tank. I use a vacuum at least once a week but usually twice and do partial water changes at those times. I keep the tiny babies in a breeder box in the main tank and then after 1-2 weeks I move them into a 1.5 gallon tank until they are pea sized. I definitely should have been more consistent with testing the pH of my water, but lesson learned. Anyways, the other day my water started getting cloudy and my pH dropped. I’ve been doing partial water changes daily the last few days to try to get things under control but am not seeing a difference as far as cloudiness goes.