New Fish

[darren636]

The PFK article suggests the filter can be off for weeks/months without much hassle...

indeed, goes against everything i have experienced since 92' though. i suppose we 'could' do lots of things and get away with it.....

 

[Antipofish]

The PFK article suggests the filter can be off for weeks/months without much hassle...

indeed, goes against everything i have experienced since 92' though. i suppose we 'could' do lots of things and get away with it.....

Question is, "Do we want to risk it !!??"

You COULD house a Polar Bear in a 15 foot cage. But SHOULD you, or would you want to ?

I had a filter that was running until 3pm and left the water in it for transport. Got home 6 hours later, emptied the water (which would definitely have been pretty nasty by then), hooked it up to the tank, added the fish in that I had already and all was well. I reckon anything longer than 12 hours would be my ceiling though.

 

[nry]

Never said we should do it

 

[dw1305]

Hi all,

I'm not talking one of those grotty blue airstones that pushes out bubbles the size of your fist I mean something decent that makes bubbles small enough that can be blown around the tank the same way the CO2 is

Yes, you are right, “EPDM diffuser“ is the term you are looking for. If you can get the bubbles small enough and keep them in solution for long enough, the gas they contain will eventually be dissolved. I've never had an air filter in the tanks, but I usually run a venturi on the filter if I don't have a spray-bar that I can position above the water level. This is the "direct aeration" bit from the dissolved oxygen article:

This means that an air pump needs to produce very fine bubbles (in the range of 10 – 200 microns diameter), that have a long “residence time” in the water column, if significant exchange of oxygen to the water is to occur. For maximum residence time and effect, unless you have a “wet and dry” or bio-wheel filter it would be advantageous if the filter intake picks up both the bubbles and oxygenated water, and feeds them straight into the filter where they will provide much needed oxygen to the nitrification process (when I wrote this I didn't realise that some-people didn't have a filter sponge on their intake and used the filter as a de facto syphon).

Diffusers and bubbles
Ceramic flat plate diffusers are one possibility for producing fine bubbles, and they are widely used in aquaculture, they have the disadvantages of being expensive, requiring high air pressure and clogging relatively easily. The other option is a membrane diffuser, which has the advantages of not clogging so easily and requiring lower air pressure. The technical term to look for is “EPDM“ (ethylene propylene diene terpolymer), and the membrane diffuser can be in the form of a disc, tube or “air wall”. These kinds of diffuser are widely used in the waste water industry, and in aquaculture, where the BOD of the water may be several hundred times the waters natural oxygen holding capacity.

i turn my filters off for feeding, sometimes i go off and do something and the filters are off a few hours, this is ok, but i would not risk more than a day or so like this.

I've accidentally done this as well, including a couple of times where I've turned an internal filter off for cleaning, and failed to turn it back on and only found out when I've come to clean it 7 days later, without any fatalities.
I'm a lot less cavalier these days, and I tend to have both an internal and an external on all the tanks that are bigger than nano.

cheers Darrel