How Much Air Flow for Sponge Filter

[Sorg67]

I have six sponge filters and an air stone running off one air pump with two outflow ports. I feeds two gang valves. I think the air flow is less than necessary for the sponges to operate properly. Not a big deal since they are all back up except for one tank and I have prioritize air flow to that tank. So I think I am okay for the moment. However, I wonder if it would be optimal to increase flow a bit.

I also have two battery operated pumps for power outages. In Central Florida, we can have power outages for several days. I am wondering if I should have more battery pumps for that purpose. I also have a 5000 watt generator. But I do not run it 24 hours. I usually run it for 10 to 14 hours during the day to run refrigerators, lights and small appliances. It is loud so I do not like to run it at night. Both for my benefit and the benefit of my neighbors.

So I would run the regular filters during the day and sponges at night.

My question is are there any guidelines I would use to determine sufficient air flow?

 

[Flyfisha]

Following with interest as I use only air to filter my tanks.

There is a school of thought that says the slower water passes though a sponge filter the longer the bacteria has a chance to consume the waste . Very sensible if you think like me that biological filtration is much more important that storing poop in one place. ( mechanical) . I find sponge filters do a good job of dropping the poop at their base in a neat pile for easy removal. As the water is sucked in and up the poop drops to the floor of the tank.

Don’t quote me but I think about 2 litres of air a minute per sponge is more than enough?