I have a 19" Waterway sand filter, the kind that is spherical. The stand pipe is approximately 21" tall and the sand bed is 9" below the top of the stand pipe currently, so its filled just over half way with sand. Does anyone know how much sand should be in this filter? All of my research only shows sand total in weight. I basically need to know how full this filter should be with 100 lbs of sand in it.
Also, I have a 1.5 HP single speed pump that was part of my filtering system when I moved in. My pool is only about 9000 gallons, and this pump seems to be too powerful for my pool (occasionally causes a vortex / whirlpool action in the skimmer basket which causes air bubbles to come out of the return). Should I think about replacing this pump?