Now I shut my filter off when doing a water change as to not stress the motor when the water levels get low. I am just kinda curious as to how long to leave it off after refilling my tank as to not upset the natural bio-filter that has formed over time in there. Since I had my disaster a while back I've been doing these changes at least once a week, but have never been solid on this filter question. I usually leave it off for at least a half an hour, what say you? more? less? good enough? even necessary to leave it off?

"I am just kinda curious as to how long to leave it off after refilling my tank as to not upset the natural bio-filter that has formed over time in there."

Your filter should contain the beneficial bacterial.. and even when you switch it off.. it will surely have some water in it.. btw.. which filter do you have???

I generally change upto 60% water once in 2 weeks.. and at that time I keep my Canister ON.. and it doesnt really affect the performance.. at all

Half an hour to an hour will not hurt your beneficial bacteria colony.
I turn of the pump, clean my pre filter and turn the pump back on.
Let it flow for a bit, while i prepare the hoses and chemicals.
Then i turn off the pump again and do a 50% waterchange.
Thet will take me about half an hour, and all is fine.
Ammonia and nitrites are allways 0.

like the other have mentioned half an hour will not harm your bb as long as there is water in the filter.
personally i dont turn my filter off during water changes (except for the tank with the sump) and it has never harmed anything.

necromancer4 wrote:


X2!!!