Calcium buildup, common in both freshwater and saltwater aquariums, creates a chalky, white crud on your aquarium. Commercial products that remove calcium buildup aren't necessarily safe for your fish and plants -- never use glass cleaner. Scrub off calcium buildup and work to prevent its return.
Signs of Calcium Buildup
Calcium buildup creates white, crusty-looking spots and streaks on the inside of an aquarium, along the edges, on the bottom of the hood and even on the filter. Calcium is naturally found in water, so calcium buildup will not harm your fish. It's just aesthetically unattractive when it forms on your tank.
Causes of Calcium Buildup
Calcium buildup is caused by mineral deposits left on and in the aquarium as the water evaporates. As the minerals sit on the glass, white spots and streaks build up on the inside of your aquarium, on the exterior walls, the hood, the filter and other elements, particularly at the surface of the water where evaporation occurs. If you live in an area with hard water, you will notice calcium buildup more often than if you live in an area with soft water, because hard water contains a higher mineral content than soft water.
Remove Calcium Buildup
You're going to need elbow grease to remove calcium deposits. Gather up a sterile large bucket, distilled vinegar and a sponge. Empty half of the tank water into the bucket and place the fish in the bucket to keep them out of the way while you clean. With the fish removed, use your sponge to apply the vinegar to the aquarium. Let it sit for a few minutes, then scrub the buildup. You may have to repeat the process until all of the calcium deposits are gone; for stubborn buildup, let the vinegar sit longer. Rinse the aquarium and all the decor carefully, then refill the aquarium. Add the fish last.
Prevent Calcium Buildup
Since it is a pain to completely remove calcium buildup from your aquarium, prevention is paramount. The best way to prevent calcium buildup is to perform regular tank maintenance, ensuring that your filter is working properly; you want to rinse out the filter cartridges, as well. The filter will help reduce the free-flowing minerals in the water but it will not remove them all. Perform partial water changes and monitor the water with test strips. You may not be able to completely prevent calcium buildup on your aquarium, but you can reduce the buildup with routine tank care.