sponge filter (natural sponge)

I think the guy that has that HUGE tank on RC uses them...I think he's got an entire tank full of them.
 
If you are referring to the 1700 stingray tank. I am only on page 150 out of 200, but I think he changed over to cheato and simlilar macro and rid himself of the sponges.

He was using cryptic sponges?

He was also keeping flow to a minimum behind his rockwork in the dark and was collecting to much crap back there and raising phosphates and nitrates i think. The thread has been a good read with a great deal of info. They are also working on a skimmer you might have been following chad.
 
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