Use white vinegar to clean the mineral deposits that accumulate at the top of your fish tank. Soak some paper towels in the vinegar and simply wipe around the inside of the tank where the water has evaporated and left the white mineral deposits. You can also use vinegar to clean aquarium ornaments. It is harmless to fish so you don’t need to worry if some of the vinegar happens to get into the water.
Using distilled water can reduce the build up of line and other minerals in the water.