Small sponge filters

I’m looking for some small sponge filters that will function well in 3” or less of water.
Any suggestions?

I do not know if they make specific sponge filters for shallow water, but my single sponge filter would certainly work here. I am attaching a photo of the double sponge filter, but these also come as single sponges, and in both cases the sponge can be adjusted to any angle from the stem so it could be horizontal to the substrate. I use this in my 10g tank.

The second photo is the Hydro sponge series; I assume the smallest would be underwater in 3 inches, but not sure..

I may end up using the single sponge filter version of the first photo, if I can think of a good way to keep it in place. The suction cups never seem to work for very long.

Herpin Man said:

I may end up using the single sponge filter version of the first photo, if I can think of a good way to keep it in place. The suction cups never seem to work for very long.

Click to expand...

Yes, I have that issue with suction cups for floating thermometers, filters and heaters. You can buy separate suction cups, but finding the right size (the hole for the prong has to fit) can be challenging.

Triangle shaped air operated sponge filter. You can remove the uplift tube and the sponge is only 1.5 inches high.

Herpin Man said:

I’m looking for some small sponge filters that will function well in 3” or less of water.
Any suggestions?

Click to expand...

Amazon has several small foam sponges at good prices. Ya think one could be laid on its side for shallow water?