Update on my air leak
This all started back in 2010 with air leaking into my system. I could see air it in the pump basket and it really bothered me. There were always little bubbles shooting into the pool. If you got into the pool, they were on you. The water was never clear when looking around under water because of the tiny bubbles. My best guess at the time was that my 1 HP Hayward Super Pump was too powerful. Being attached to just two returns couldn't supply it enough water and it found a way to pull in air
In 2013 I switched to a 3/4" HP Hayward Super Pump thinking less power would eliminate the air leak. This kind of helped initially and the air leak came back not too long after switching (in retrospect, it may have come back after I added a winter safety cover). I lived with the air leak for the last 5 years.
Skip to present day early summer 2018 and I had to replace my vinyl liner. Had to redo all my fittings and was thinking maybe this would fix any air leak. Hoping the problem was at a connection to the black poly all along. This was just a pipe dream. The air leak persisted. But my pool liner guy said I should just pressurize my system and look for leaks. I could pour soapy water on the above ground stuff and look for bubbles.
I didn't think much about this. I have had an air leak for the last 5 years. Just learned to live with it. Then a few weeks ago my pump went bad Decided to go with a 1/2" HP Hayward Super Pump. Hoping this would get rid of my perpetual air leak. Maybe the 3/4" HP Super Pump was also too powerful?!?!. I had been using the 3/4" HP Super Pump for years with an air leak. Well, when my filter was clean after backwashing there was a leak, but when the pressure went up about 4 PSI in the filter, the leak would go away. Really hoped the 1/2" HP Super Pump would just have less suction and would fix my air leak problem. Switched out the pumps a week ago and the problem was worse!!!!
I hooked up and air compressor to my system as recommended by my pool liner guy, just like when I winterize the system. Plugged up all the intakes and output. Turned my sand filter to closed. Found air leaks in the two threaded pieces that screw into the super pump. I was so excited I found an air leak. I replicated the leak a few times to make sure I wasn't dreaming. Then after I had played around a while watching the leak I found, I had to go tell my wife so she could see. As I was walking to the house, I saw water and air bubbles shooting up out of the ground. It was right next to where I had put in a metal tube that holds in my winter safety cover. I dug down and the metal tube was directly inside of the pool return line (black poly) I probably installed that around 2012 or 2013.
So I went and fixed the black poly with a two sided barbed connector. I used a heat gun to get the black poly pretty warm, applied RectorSeal Tru-Blu pipe thread sealant (vibration resistant) to the barbed fitting and it went into place super easy. Double clamped the fitting in place for good measure.
Did some research on leak proofing my threaded PVC at the Super Pump and sand filter and found out I shouldn't be using teflon tape. Found LA-CO Plato-Joint Stik
https://www.amazon.com/gp/product/B004MYFP8C
Both fixes worked like a dream and got rid of the air leak 100%. The first time in 8 years I have gotten rid of the air leak. I am so happy.
My take aways - use a pipe sealant when putting together threaded PVC AND be sure it is the correct pipe sealant. In my limited experience with PVC, the LA-CO Plasto-Joint Stick is awesome and teflon tape kind of sucks. For putting together barbed pieces for black poly my pool guy recommended a silicon sealant (not caulking). I used the RectorSeal Tru-Blu which isn't exactly that, but it is along similar lines. It lubricates, will stay flexible, and filled in any tiny imperfections that may have lead to a leak.