Skimmer suction issue - low and surging


Jan 26, 2018
Houston, Tx

when when I have the suction valve set to skimmer and main drain or skimmer only I get inconsistent suction and lots of air bubbles in the return. The water in the pump basket rises and falls and the pump does Not really prime.
When I have the suction valve to main drain only everything works great.
In spa mode everything works fine also.

What gives? Thanks for you help.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Your pump is sucking in more water then your skimmer can provide. Just leave your main drain open some so your pump gets water from both lines.

Is your weir door swinging freely and opening to not block the water intake of the skimmer?


Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
Sebring, Florida
If the weir door is free, is the water level in the pool high enough so the skimmer is not sucking air? Check it while the pump is running.

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Also curious if you have a suction-side cleaner that plugs into the skimmer? Done any vacuuming lately to where you may have sucked-up something a bit large perhaps into that skimmer suction line?

PS - Don't forget to update your signature with all of y our pool and equipment info so we can see what you have there. :sneaky:


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

A pump can't suck more water out of the skimmer than can "fall" in from the pool.. If your skimmer seems to empty, then fill up again, over and over, then your water level is too low or your skimmer door is stuck up.


Jim R.