I've had my 12 gallon aquarium up for 25 years. Sometimes as a terrarium, but mostly as a fish tank. It serves to help put moisture in the air, water my plants, and occasional cats, but mostly as a way to store my antique glass battery case that was my grandfathers. I currently have way too many fish, Mollies. They just keep breeding. I also have 2 shrimp (they've been in for 4 years) My main problem is lime buildup on the glass. What if anything can I do to prevent this? I don't use a light, and have fake plants. I just removed all the plants for cleaning, that's why it looks so bare.