Canister filter uses??

[Cap'n]

I consider my canister filter (round eheim 2215) a major part of my filtration system. I have a mixture of sand and ceramic cylinders as my bottom layer, followed by a large area of ceramic cylinders, then coarse gravel topped off by a mass of plastic netting. I can see the pods crawling all through the sand and cylinders when I look at the side of the unit and find numerous stars and worms every time I clean the filter. I wouldn't go without one. Quiet, efficient, mechanical filter that has become quite a bio filter as well.