I just found these as add on sponge filters for HOBs. It fits all cylindrical intake tubes. Protects against fry being sucked up. Also adds more surface area for beneficial bacteria to homestead. I will report when they come in and provide pics. I have been hunting for them for a while. If you want to know from where I ordered them, PM me.
Smile, it makes folks think that you're up to something.
I second using the AC sponge. Its coarse larger cell holes don't restrict flow as much. You can cut 2 or three inlet tube filters with one block of it.
But you can't go wrong with what you ordered either. Its all good.
A 37 GL but its really 27gl when full
Security at the expense of freedom results in neither.