The way I look at it. If you use an inter-tube you have to worry about poking holes in it or the sun beating down on it making it hot to the touch. Now if you use PVC I would use 2" pvc and glue into 2" 90 degree elbows so water can't get in and it will be air tight. Use plastic ties for your screen. The frame will last many years, just changing screens once a year or so. I have a wooden sifter I used many years ago screening arrowheads out of the lake. It's made with 2x4's for the frame and rabbit wire for the screen stapled to the 2x4's and a 1x2 covering the staples for extra support. It holds alot of mud and floats. This is just my opinion on what to use. Other people use only inter-tubes, I say "whatever floats your boat". Cliff