Sponge filters per tank size?

[Kikojaharo]

Seeing as how these double sponge filters are pretty much the standard, I'm surprised I haven't found yet a guideline as to how many gallons one filter will be good for.

How may gallons can this sufficiently filter, for the sake of, "I need X amount of filters for a tank of Y gallons"

Of course, I'll use an HMF in a tank that would need something like 3 or 4 of those.

On that same note, would 45 pores per inch be too dense to serve as a filter sponge?

[OMG Aquatics]

For tanks where pH is over 7 and can easily recolonize bacteria, I would do 1 per 10G.

For tanks where pH is lower than 6.5, I would do 2 per 10G since bacteria recolonize at a slower rate.

 

It also depends on stock amount and stock waste.