Sponge Filter...but How Much Sponge?

[Curiosity101]

I know it seems silly but how much 'sponge' should I expect to get for a sponge filter capable of filtering something between 60-80l. I presume I'd aim for something with more sponge than the average power filter meant for a tank that size due to the fact that the air pump running it wont pull the water through as fast as a power filter does?

I may well make my own (simple uplift tube, bung the bottom, drill holes and push into sponge), but I still need to know how much sponge to use.

To help it's likely to be on a fry grow out tank...somewhere between 60-80l ish.

 

[holidayinn]

I made a homemade sponge filter, for my fry grow-out tank for my RTMs, used the biggest TetraPrima container I had and one sponge from a fluval 4 filter, some gravel..job done, works a treat! Sorry, that prob doesnt answer your question, but its my experience of sponge filters.

 

[Curiosity101]

It's helpful if you tell me an 'ish' amount on the bioload? As in how many fry up to what sort of size
Also what size was the tank? And what size air pump (lph) did you have on it?

 

[holidayinn]

It's all at home, and I'm doodling at work

Bioload was about 25-30 Parachromis 'Red Tiger' Motaguense, under a cm at the beginning, now almost 1.5" (still in the tank, trying to re-home stock).

It must be approx 15 gallon tank, roughly 2.5*1*1...The Air Pump was quite small and this will dictate the lph, I honestly cant remember what air pump it is except it's the smallest one I have (sorry, not much help atm I'm afraid). I would next time definitely put a stronger pump on as I think it'll help sustain the flow rate longer term.