Air bubbles in my filtration system

TomAtlanta

Well-known member
Sep 10, 2011
392
Atlanta Ga
There are lots of air bubbles in the water returned to my pool. This has happened on and off, to a lesser degree, since I got the house with the pool 3 years ago, but now there are lots more bubbles and it is constant. My regular pool guy could not figure it out, so in a month when it gets warmer I will get the high tech leak detector guy out here. My question is - Does running the system with all the air going through it do any damage to the pump, or to anything else?
 
It should be a suction side leak, most common problem is the lid or drain on the leaf canister at the front of the pump. I had a similar problem and fixed it by replacing the drain plug and seal. As to damage a little won't hurt but a lot might.
 
Before you call a pro, there are a few things you can check easily.

First, look for anyplace that the system spits a bit of water when the pump shuts off. That is a classic sign of an air leak.

With the pump running, look in your skimmer and check that there isn't a whirlpool showing up and that the skimmer isn't making any noise. Make sure the weir is laying below the water surface and that it can move up and down freely.

Shut down the pump and remove the pump strainer lid and inspect the O-ring for cracks or distortion. Lubricate the O-ring if it is good, replace it and lube the new one if it isn't. Reinstall the lid and be sure you get it tight.

Remove the strainer basket drain plug and inspect the O-ring. Same deal as the lid O-ring. Lube and reinstall, with a new O-ring if needed.

If those efforts don't fix it, get your garden hose with no nozzle and watch for bubbles in the basket while flowing water over the pump inlet joint and any valves or fittings on the inlet plumbing. If the bubbles reduce while you have water running on something, it is probably leaking.

If none of that shows a problem, before you call for help, I'd try digging down to where the pipes that come from the pool to the pump inlet go into the the ground. The very first elbow that will probably be a foot or less underground is a common source of leaks. You should see dampness around it with the pump off if there is a problem.

Another possibility is that you have a restriction of some kind in your plumbing on the inlet side. Toys, rocks or leaves can cause bubbles in the basket. If you have a drain and skimmer both, try closing each to see if the bubbles are better or worse on one or the other.
 
As to damage a little won't hurt but a lot might.

How does that work? Over heating the pump?

- - - Updated - - -

Thanks for the great info John. A few questions


before you call for help, I'd try digging down to where the pipes that come from the pool to the pump inlet go into the the ground. The very first elbow that will probably be a foot or less underground is a common source of leaks.

Unfortunately that is under concrete deck, so I will need the pro to put his camera down there.

Another possibility is that you have a restriction of some kind in your plumbing on the inlet side.

How does that work? How does that let bubbles in?
 
It doesn't let air in, but without enough water going in you get bubbles.

If that is the problem you'd notice a drop in filter pressure from the normal gauge reading.
 
If the skimmer is clogged, then your pump is pulling more negative pressure between the clog and the impeller. This added suction could result in air being pulled in around a seal that would not occur under normal suction.
 
I tried all the suggestions above and never could find the air leak. A pool guy said that just by the process of elimination the leak is probably below the skimmer, either in the first joint, or where the pipe connects to the skimmer. The problem is that this is all under a concrete deck and would be expensive to get to, so I am probably just going to live with it.

In the mornings when I turn on the system, some times the pump won't prime. I switch to rinse which gets rid to some of the air built up in the filter and then it works. I would rather not have to do this. I don't really understand exactly what is going on because the pump and filter are down hill from the pool.

The pool guy said that putting in a check valve between the filter and pump would reduce the priming problems by keeping air built up in the filter from going back into the pump and the pipe between the pump and the pool. Another pool guy said a check valve would have no effect. Any thoughts on this?
 
You can build a rig that will allow you to pressurize your skimmer line with air pretty easily and cheaply to verify that you have a leak.

If your pump is below the pool water level, how is the water flowing out of it overnight? Have you checked your waste line for flow?
 

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