This is my mechanical prefilter material. I did some measuring to see how much PVC pipe it would take. I figured on how many elbows I would need. I brought my pump to my local hardware store to be sure PVC tubing would fit the outflow of the pump. Because I planned to place this basket upside down in the bottom of the batting-filled prefilter to keep the batting from clogging the pipe.
Water comes in under pressure but leaves at a lower rate, but in greater volume, via gravity.
It's buried at the bottom of all that gravel. The little holes keep the gravel out of the pipe but let the water flow in. But these are the holes that sand can clog. So I sifted and washed my gravel to eliminate sand and tiny particles. An end-cap on this pipe was not necessary, it's open at both ends.