Turbulence pool filter/oscillating pressure gauge

A.B.

Member
Apr 22, 2025
9
Louisiana
Hi guys,

My pressure gauge is oscillating on my filter. Also the check valve is rattling on the in-line chlorinator rainbow 320, I opened it up with the clorinator off and pump running... I could see air bubbles coming up in the water inside the chlorinator.

There is a micro drip leak at the T point after the chlorinator ( two drops of water in 3 hours I tested twice with a parchment paper under it)

But from what I've read, leaks after the filter should only cause water leak not air.
It seems there is air in the filter somehow. After backwash and rinse the gauge stabalizes for a couple hours and then air builds up and makes it oscillate (tested this twice). I took off the pressure gauge to re-seal with teflon and when I removed it there a blast of air that comes out with it.

It has not had any adverse effects on the pool, no air bubbles I can see. I think the air is just having a good time inside the filter and chlorinator.

I plan on replumbing the leaking T this weekend. But I'm concerned it maybe something else. Pool pump basket is full/ no air bubbles in there. Problem seems to start at filter. What do you guys advise I check?

Thank you.
 
RECIRCULATE bypasses the filter. No water should be flowing through the filter and PSI should be 0.

hm,

the pressure gauge is on the filter head...

it shouldn't show any PSI for water flowing through? It also shows psi during backwash and rinse btw...

Pad is at the same level as the water.. here a pic, pardon the water its been raining today.
 

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hm,

the pressure gauge is on the filter head...

it shouldn't show any PSI for water flowing through? It also shows psi during backwash and rinse btw...

Pad is at the same level as the water..
Backwash and Rinse are flowing through the filter.

Recirculate should bypass the filter.
 

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Bleed all air from the system in filter mode…..once bled, turn off the pump and immediately switch to recirculate, restart and verify if the gauge oscillation problem persists or if you see a pressure reading at that point.
 
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Thanks guys,

I took off to the top assembly to check the spidergasket, its good and I did re-lube it. When I was trying to take the top off I noticed there was a ton of air pressure which I had to bleed to get it off. The air seems to be staying trapped there at the top of the MPV.

The air release bleeder is not removing any air (just water coming out). Pressure still oscillating. When I remove the gauge as soon as I shut off the pump, a blast of air comes out.
 
I suspect the air entrapment is your issue, causing the gauge fluctuation, and pressure readings in recirculate mode. I’d be suspect of anything related to the rainbow allowing air in. If water can escape, air will get in. How old is the unit? Does your pump shut off at any point during the day? My opinion is rainbows are junk new out of the box…..inspect all tubing, check valves, the housing etc….or just delete the unit and save yourself headaches.
 
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ok, this is what I suspected. I will update here if the re-plumbing this week fixes it.

I was just confused by something I had read here that leak on return side causes water not air.. But makes sense to me that air maybe travelling up to the filter due to the water going the other way.