Decline in flow rate during pool activity...

[markarin]

Howdy! First post, but have been lurking quite awhile... We built our first pool last year and started it up at the end of last October. Startup experience has been great, but now experiencing some occasional weirdness. Nominally, we have excellent 30 GPM flow from our IntelliFlo VSF pump at 1500 RPM; however, when we as a family get in the pool and the water gets sloshing around, the flow goes to virtual nil coming out of the return jets. Flow returns back to 30GPM when I crank the RPMs up to 2500 or so though. Overnight, after we get out, things seem to stabilize, with 55 GPM at 2500 RPM in the morning and a perfectly still water surface. When I return to 1500 RPM, flow also returns to 30 GPM as desired. Water level is where it should be, not excessively high or low...about 3" below the bottom of the edge coping. No water feature sheers or bubblers running. Skimmers and pump screen filter all clear.

Thoughts?

 

[hexabc]

Howdy! First post, but have been lurking quite awhile... We built our first pool last year and started it up at the end of last October. Startup experience has been great, but now experiencing some occasional weirdness. Nominally, we have excellent 30 GPM flow from our IntelliFlo VSF pump at 1500 RPM; however, when we as a family get in the pool and the water gets sloshing around, the flow goes to virtual nil coming out of the return jets. Flow returns back to 30GPM when I crank the RPMs up to 2500 or so though. Overnight, after we get out, things seem to stabilize, with 55 GPM at 2500 RPM in the morning and a perfectly still water surface. When I return to 1500 RPM, flow also returns to 30 GPM as desired. Water level is where it should be, not excessively high or low...about 3" below the bottom of the edge coping. No water feature sheers or bubblers running. Skimmers and pump screen filter all clear.

Thoughts?

Is all the suction through the skimmers (no drain)? It's possible that skimmer weirs get stuck in an upward position. When you switch the pump to a higher RPM, the weirs get unstuck.

 

[markarin]

No, there are two skimmers and also two main drain inlets at the bottom of the deep end.