I have one of those blue sponge scrubbers sold in the pool section at the big box retailers.

I have an 18' 52" deep above ground with a Hayward sand filter. I think the pump motor is a 1 HP. I use 1' chlorine tablets with a floater and 1 pound bags of shock. I have a basic ph and chlorine re-agent tester and have some strips but I know those do lack accuracy.

I think this is my 4th or 5th season with this pool and I generally have little problems maintaining clear water. I use a cover in winter to keep out leaves. It gets full sun until about 3 to 4 PM.