I used to have ramshorns for years in my tanks. Generations of inbreeding tended to start producing snails with little shell coloration and sometimes even transparent shells. Maybe something like that is happening here.
I don't think that's the case here. I haven't had them for more than several months. I think it has something to do with a lack of calcium or minerals or something in the water, but I don't know exactly and trying to find out. I don't have so many that they're a problem. I like their clean-up efforts and would like to have them around.
They do a good job at cleanup. You will have a lot of them eventually if there is enough food for them to eat. I liked them a lot for their cleanining abilities too. There is some debate on how good they are for your tank though. Some find them to be a nuisance. I didn't mind them.
Not sure what is going on with the snails you have though.
Yeah I believe it is a lack of calcium and other minerals. There was someone on here that started raising snails and got a special substrate to get the minerals in the tank and the shell coloration was noticeably richer. My apple snail shells are suffering in my water, they are white and rough when they were yellow and smooth.
If your snails are suffering becuase of low ph, you can buy some tumms and drop them in. i Had about 300-400 apple snails within 2-3 hours of a water change they sucked everything out of the water dropping it to 6ph and below. I put 3 tumms tablets in there and they were gone in about an hour lol