I have an inground pool which is losing prime overnight. If I turn off pump, I see a single air bubble form every 5 seconds or so in the filter basket housing of the pump. I went through the following steps to try and isolate the issue..
1. Skimmer/Drain closed, multiport on "closed" - no air leak
2. Skimmer/Drain closed, multiport on "filter" - air leak
3. Skimmer open, Drain closed, multiport on "closed" - air leak (I can hear air moving in the multiport)
4. Skimmer closed. Drain open, multiport on "closed" - air leak (I can hear air moving in the multipart)
5. Skimmer open. Drain open, multiport on "closed" - air leak (I can hear air moving in the multipart)
I already sprayed soapy water on everything, and was not able to see any bubbles get sucked into anything.
The above steps lead me to believe there is an issue with the multiport, like perhaps the spider gasket. The one thing that has me confused is why on #2, do I not hear any air moving in the multiport even though I still have the air leak? Only thing I can think of is that when the skimmer or drain is open in #3 or #4, there is more of a vacuum which sucks more air, and thus I can hear it. Thoughts on my theory? Should I try replacing the spider gasket?