How long can I turn filter off for?

[yvez9]

I had a 3 hour power outtage about a month ago
I have 2 filters and 1 went dry and when i cam back home, all the bacteria had died off in it and the motor was really really hot. Luckily, the other filter was still running fine so it took about a day for the bacteria to colonize the 2nd filter.

on the other hand, I've transported media from my place to my girlfriend's. The media was in a wet plastic bag for about 45 minutes and the bacteria were fine

 

[SarahBravo]

Yeah, with the Juwel built in filters you have to turn them off during water changes, a) for electrical safety and b ) because otherwise they'd probably run dry and damage the impeller.

I've had mine off for an hour and more when re-aquascaping the tank, without any problems. The way they're built they'll stay wet for a fair while. I guess if it was going to be longer than one or two hours, take the sponges out, put them in a bucket of tankwater and put an airstone at the bottom of the bucket and that should keep them going for a few hours. During normal water changes I just leave the sponges in the filter, it's never caused a problem.

HTH

Sarah