I'm not certain on this, but I wouldn't do it. I'm running on what they tell you when it comes to curing LR. You know, 'make sure all the dead stuff like sponges' are scraped of before adding them to the tank.
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55gal,216 watt Tek T5, 45#LR, 45#LS, 3 maxi-jet 900's on a natural wavemaker timer,phosban reactor, 5 gal fuge (built out of standard 10 gallon tank) with chaeto and feather caulerpa, sealife systems protein skimmer, wet/dry, 3 blue/green chromi, 1 skunk cleaner shrimp, 1 coral beauty,1 scopas tang, 2 false percs, 5 mexican turbo snails, assorted dwarf blue leg hermits, astrea snails, and nerite snails | 
Dead sponges as bio filter? 
jb
hey, it may look nice with conch shell collection! Thanks guys! was just wondering if it could serve any functional purpose.
