Troubleshoot sand filter


Active member
Jun 23, 2008
I have a Doughboy sand filter (225 lbs sand capacity), 2 speed, 1hp pump, Above Ground Pool.

I just replaced my sand media with zeobrite, hoping my pressure would drop.

It didn't.

My pressure gauge reads 19 psi on basic skimmer, with pump on high, about 8 psi on low speed. That seems too high, doesn't it? I did followed all the backwash instructions for installation, and it IS keeping the water clean. But, I feel something is not right.

Last season, I took the filter lid off, and I'm not sure I put it back on right, or maybe that something didn't seal properly. (My uninformed theory is that the center pipe isn't sealed tight and so the pressure is building up at both ends.)

But, how do I troubleshoot that? What do I look for? How can I determine if/when my filter is working or optimized?

PS: I don't have an owners manual to consult.

Thanks for your help.


Mod Squad
TFP Expert
Apr 4, 2007
SW Indiana
Higher pressure would indicate resistance to water flow, so I'd think any sealing problems would tend to cause water to bypass the filter, giving you low pressure. A couple of things to check: What kind of reading do you get when the valve is set to recirculate? How about if you remove the eyeball fitting from the return? Does the pressure gauge return to zero when the pump is off?