I was comparing the ENTIRE internal and external surface area of the sponge with the entire surface area of bio media. Its still over a 50-1 ratio.
Which is 45ppi still over 35 times less surface volume ... if anyone thinks this filter will do a 125g well stocked tank they have no idea ..... it won't.First of all, with sponges, it's not all about surface area. Seeing how water flows through the pores of the sponge, the area that bacteria in propagate exists throughout the entire sponge, not just on the surface as you try to imply.
And I never said anything about 30 PPI sponge material. I SPECIFICALLY have always refered to sponge material as used on the hydro line of spnge filters.
http://www.thatpetplace.com/pet/prod/203832/product.web
That filter can handle up to 125 gallons, so go on and tell me how poor a bio media it is. The problem with sponge filters is there is no profit margin, so stop drinking the kool-aid.