SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/fish-filter-media-rinse

How should you rinse mechanical filter media?

In dechlorinated or old tank water, never straight tap water.

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  1. Under hot running tap water
  2. In soapy water
  3. In dechlorinated or old tank water ✔

Why: Chlorine in city tap water kills the helpful filter bacteria. Rinsing in treated or old tank water cleans out gunk and keeps the bacteria alive.

Huh, didn't know that: Chlorine and chloramine in city water are toxic to fish and to the helpful bacteria.

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References

Answer: In dechlorinated or old tank water. Chlorine in city tap water kills the helpful filter bacteria. Rinsing in treated or old tank water cleans out gunk and keeps the bacteria alive.

  1. Texas A&M Extension: Gold Rush, A Kid's Guide to Goldfish Care extension.rwfm.tamu.edu/wp-content/uploads/sites/8/2013/10/Goldrush-%E2%80%93-A-Kid%E2%80%99s-guide-To-Goldfish-Care.pdf
    The bag in your filter should be rinsed with dechlorinated water at least twice per month
    Checked 2026-10-11.
  2. Merck Veterinary Manual (pet owner): Providing a Home for Fish www.merckvetmanual.com/all-other-pets/fish/providing-a-home-for-fish
    chlorine or a combination of chlorine and ammonia (known as chloramine), both of which are toxic to fish and to the necessary bacteria
    Checked 2026-10-11.

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Fish & AquariumsWhy do you add dechlorinator to tap water?Fish & AquariumsIn a long power outage, how can you keep your filter's helpful bacteria alive?Fish & AquariumsMany cities treat tap water with chloramine. What is chloramine?

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