recently i got a filter, and when im cleaning the tank, the instructions of hte filter says that i shoudl turn the filter off.

is it okay to turn the filter off for half an hour or so while i vaccum and chnage the water? or will there be an increase in ammonia or soomething becuase i turned it off?

i always wondered wehther the debri caught in the filter will fall out into the water when i switch it off, as there is no more sucking motion of hte filter?

thanks.

Well, with most "hanging" filters, you have to turn em off, cuz during water changes, the water level drops too low for them to work. I have mine off for about 20 minutes or so, but half an hour might be too much. It's not the ammonia build up that can be bad in that amount of time, it's the anerobic bacteria that can start up in the filter. Then, when the filter gets turned back on, it dumps it into the tank. I've never had anything bad happen though, and I've had it off for about 30 minutes before, but I try to keep it off for the shortest possible amount of time.
No, it's not gonna fall into the tank (the caught debris). It's stuck in all the spongy stuff, so it doesn't go anywhere.

It would take much longer than half an hour for anaerobic bacteria to grow and multiply enough to become a problem in a filter that has been turned off. I would have thought that the only problem you would get would be if it was turned off for long enough to actually dry out the filter media and thus reduce the levels of the the good bacteria you have worked so hard to get on the filter media.

And Shelly would know.... she's a microbiologist!! Now if she will only find me an old test tube stand and some potassium permanganate I'll be really happy...

Hi Shelley, can you give an estimate on how long you could safely leave off a large filter?

Cheers! Annette

so is it true that its bad for your gf if you turn badck on the filter
and they are quite near it? as it "dumps" the bad bacteria right into the gf? i feel really paranoid about turning on adn off the filter!

Sorry guys. I am by no means an expert of fishtank filters as I am very new to all this. All I am fairly sure of on this topic is that anaerobic bacteria are usually quite fastidious and not prolific growers in that they would not take over a filter media in a short period of time when turned off. While I am no expert in fishtank filters my commonsense would tell me that not much harm would be done to a tank if the filter is turned off for short periods of time. And I am sure that once turned back on it would balance out again. But don't quote me on this, as I said I am new to this hobby.

BTW, fancyfins I have your test tube rack and will look for some potassium permangenate today.