Get a room size dehumidifier. Use the exhaust fan or crack a window. Too many chemicals in the tank can cause the mechanism to deteriorate. Drain and clean at least once a month to keep developing mold at bay. You must live in a humid climate or have poor air circulation in the room.
build up where in the tank?? in the room? outside the tank?
You need to change the ph of the area. Baking soda will do a great job and wipe with vinegar water.
use peroxide .I clean my tanks and toilets with it .I have a well with water that has some iron in it and we all know that leaves an orange stain .Peroxide solves that .88 cents a bottle in Walmart and a dollar at dollar stores and it works and will not harm the insides of the tank workings.My mom used it when I was growing up and I am now 65 years young and still use it