It doesn’t prevent them from getting food I put food in for them I put Algea wafers and I put egg shells in. also question , can I put reptile powder calcium in for them ? To grow strong shells ? Or is that not good .
Do not put reptile calcium powder in a fish tank containing fish.
If you want to increase the mineral content of the water, add a Rift Lake water conditioner at a lower dose. However, you should find out what the pH, GH & KH of your water is first. If you already have hard water, you won't need to add anything. A GH of 150-200ppm should be ample for snails to develop good shells. Keep the pH above 7.0 so the acid water doesn't dissolve their shells.
You can contact your water supply company via phone or website and ask them what the pH, GH & KH are. Find out what the GH & KH are measured in (ppm, dGH, or something else). Their website will have this information in a Water Analysis Report. You can post if here for people to go through if you don't understand it.