Bubbles in the Pool

Finally! After many months of tracking it down, at long last, I've solved the mystery of air bubbles entering the pool from the returns as they're called. These are the jets that shoot water back into the pool from the filter.

Bubbles From a Return

When something has gone wrong, air bubbles appear and come into the pool from those same jets.

If the bubbles are coming into the pool from anywhere other than the spa jets (where you want bubbles), the bubbles are an indication of something amiss.

Bubbles anywhere else in the pool means the pump is pumping not only water but air through the system as well.

This causes problems in several areas, the pump, the filter, and the piping. Decreased filtering because of excess air can lead to water quality problems, and potential safety hazards, like the possibility of the filter rupturing, in my case, a sand filter with a large tank.

There are basically two sides to the pool pump. The suction side and the pressure side.

A Hayward Pump Example

The suction side draws water from the pool, from the pool skimmer, vacuum cleaner, or the pool floor drain, for example. The pressure side returns water to the pool from the filter.

The dividing line between the suction and pressure sides of the pump is the impeller.

Before water gets to the pump, the pool pipes are under some vacuum pressure or suction, and any gap or hole in a pipe, fitting, valve, or gasket, such as an O-ring, will suck air into the pipe or the pump. I don't know how much vacuum pressure the suction side is under, but on the pressure side, it is usually anywhere from 20 to 50 pounds.

Any leak that begins on the pressure side of the pump will generally, be relatively easy to find because it will leak water. I've found that pressure side leaks are much, much easier to track down and solve.

An air leak will probably be visible in the pump strainer cover, which is a transparent cover for that very reason so you can look for the presence of air bubbles.

There's a whole bunch more to troubleshooting pool air leaks. Generally, you would start with the easiest causes and work your way on from there.

The threaded pipe entering the pump might just be sucking air. I just removed mine and put a good twelve wraps of Teflon tape on it before re-threading into the pump body. I made sure it was tight by using my pipe wrench to ensure it was really tight. This fitting can be an ongoing source of leakage, as it is really susceptible to vibration or other problems.

There's a little drain plug in the front of the pump right near the bottom. It's easy to overlook this when checking for air leaks. There's also a drain plug at the back left side of the pump housing body, but that's actually on the pressure side of the pump, so it's no worry in this instance.

Leaks can also develop from worn diverters, ball valves, couplings or unions. Control valves from the skimmer, main drain, or vacuum cleaner might be in the wrong position. Incoming valves might have worked loose. The strainer cover might not be tight enough. It has a large O-ring that might be stretched out of shape or missing.

I've read that there is a way to check for air leaks overall on the suction side, by pressurizing the system from the skimmer, using a Drain King at the skimmer, and a plug in front of the pump. I've never done that. They're sold to unclog household plumbing, so it's an idea to keep in mind if you've reached the end of your rope, bubble-wise.

It can drive you crazy tracking down an air leak. I chased my air leak for at least several months. Before that, For years, I had an intermittent air leak that showed up, then went away of its own accord after a while. Try troubleshooting that.

I finally found my air leak this morning. It was a combination of the threaded pipe enting the front of the pump and the little drain plug at the front near the bottom. Once I re-wrapped the Teflon tape on the threads and tightened the drain plug - no bubbles. Life has suddenly become good again. Now all we need it for Mother Nature to stop refrigerating our air and we'll be back in the pool in no time.