Hydrostatic Main Drain Valve

carlbob

Member
Mar 7, 2016
19
Arlington tx
Here's a question for you scholars. Pool Water has been dropping at a fast rate. Did the bucket test, and the pool lost 1/2 inch of water from the bucket and over 11/2 inches from the pool in 24 hours. I've dye checked everything but the main drain and can see no signs of a leak. There are no leaks with anything on the equipment pad. I've done a lot of reading and have my suspicions its in the main drain area. I haven't dived down yet to remove the cover and check things out since the water is only 72 degrees. My question is, can a bad hydrostatic valve leak water out but yet let air in. The reason I ask is that when I turn my jandy valve on to just main drain suction I get a lot of air in my pump basket, but when on just skimmer suction the pump basket is clear. Anyone have any ideas??
 

borjis

LifeTime Supporter
Aug 19, 2014
3,000
Pacific NW
I had some clogging in my main drain (pine cones) that caused the same symptom when
I filtered or drained with main drain only. So possibly?
 

pooldv

Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
Aug 10, 2012
25,408
FL panhandle
Sounds like a suction leak on the main drain line that sucks air when the pump is on and leaks water when the pump is off. I doubt you have a hydrostatic valve, I've never seen one installed in DFW.