I got a frag of gsp (thanks botchmac77). I attached it with a rubberband on to a rock, it's been sitting stationary. Yesterday I forgot to fill my return chamber( I don't have ato yet), water evaporated and I got some microbubbles blowing out of my return pump nozzles. It blew my frag off but I noticed something white and spongy under the frag. Can anyone tell me what it is?