Shell turning white?

This radix snail’s shell is turning white, it’s my biggest snail and the only one affected this much, but the other older individuals are showing signs of this too.

Notable malfunction: I had an aquarium heater, and the water was hitting 89f daily and I wasn’t sure why. Turning off the heater, the aquarium is at 76f even when the room is 68f, so I’m assuming the filter vibrations or being next to our internet modem keeps it warm. It took a week for me to notice, and I bought a temperature gauge.

It’s a 3 gallon aquarium, that pothos is artificial and the ends where the wires are have been sealed with cyanoacrylate glue. There’s a thick piece of cuttlebone floating at the top of the aquarium, it is unflavored.

I do not have a testing kit for water parameters yet, but my pond snails just made a shitload of babies, none have died as of yet, and I do water changes at regular intervals (50% water change, is this overkill for a 3 gallon?)

The substrate is generic black sand from imagitarium, and the kit is just a walmart 3 gallon “goldfish” tank. (Fish are not going to be placed in here. With luck, cycling, and a little more practice, this will be for shrimp.)