Need to add sand to filter?

[phipatch]

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?

Thanks!

 

[BoDarville]

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)

Based on that information, I would agree with you that 1.5 HP is a bit much for a 9,000 pool. Not uncommon, since there is a tendency for installers to go with a higher HP pump than needed.

Replacing it is your call. If it were me in that situation, assuming the current pump is a single-speed and running on 115 volts, I would replace it with a 1 HP 2-speed pump along the lines of this: http://www.amazon.com/2-Speed-volts-Above-Ground-Pump/dp/B000A4TDEK/ref=pd_sim_sbs_lg_51

 

[duraleigh]

+1 what BoDarville said. :lol:

I'll make a general statement and say most sand filter operate well being 2/3 full. 1/2 is not enough and 3/4 is likely too much.

 

[phipatch]

Thanks for the link! Current pump is 115V. So I would use the low setting for normal filtration and circulation, and switch to high for vacuuming and backwashing, correct? Waterway's site shows the turnover through a 19" sand filter to be 16,000 gal in 6 hours at 45 GPM, but doesn't specify if thats on high or low setting. Assuming thats on high, would the low setting produce about half of that flow rate?

 

[BoDarville]

So I would use the low setting for normal filtration and circulation, and switch to high for vacuuming and backwashing, correct?

Yes, that's correct.

...would the low setting produce about half of that flow rate

Correct again. The other benefits of the low setting is that it will use much less electricity while providing better filtration.