filter

Hey, I 've had a cylinder Eheim filtration system and was wondering the proper cleaning techniques involved. I've washed off the sponge part but besides that what else is required.
Also I've had a group of polyps and a plate that died very close to eachother and wondering what might do them both in at the same time
Thanks

On you canister,just make sure your getting all the gunk out of it.
As for you polyps and plate,what are your water parameters?