Can tap water be used during filter cleaning?

Cleaning your filter with tap water can be a fast-track ticket to disaster. The chlorine and/or chloramines in municipal water will destroy the beneficial bacteria in the filter in minutes. These bacteria are responsible for breaking down the toxic fish waste. Without them, your ammonia levels will spike to deadly levels very quickly. In my early years, I have seen tank wipeouts due to this error.

Municipal water contains 1-4 ppm of chlorine according to EPA guidelines. Chloramine-treated water will remain toxic for a period, even after it has been left to sit. Either compound, upon contact, will destroy colonies of nitrifying bacteria. Gasping fish and lethargy can appear within hours after an ammonia spike. Always test the water parameters after performing maintenance.

Be prepared before embarking on filter maintenance! Buckets should be reserved for aquarium use only and not for cleaning utensils, as they may be contaminated with products that could poison your fish. Have a bacterial supplement, such as JBL FilterStart, on hand. Ensuring all water temperatures are the same as your tank's is advisable, as temperature shocks will kill off bacteria quickly.

Rinse all biological media in a colander using tank water. Swirl the components around in the water until the debris starts to fall off. NEVER squeeze ceramic media! Change chemical media, such as carbon, every quarter. Always reintroduce bacteria when cleaning. Your fish will love you for it!

Read the full article: Aquarium Filter Maintenance: Essential Care Guide