Why Are There Two Holes At The Bottom Of The Pool Skimmer

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Pool skimmers keep the surface of swimming pools looking beautiful and free of floating leaves, insects, and other debris. However, household swimming technology is complicated, and you may wonder why there are two holes at the bottom of the skimmer basket. Each one fulfills a crucial function that keeps the device running smoothly.

Let’s discuss the parts of a pool skimmer and what they do, including the two holes at the bottom. Once you get a clear picture of how the device works, we will wrap up by answering some frequently asked questions.

The Parts of a Pool Skimmer

The pool skimmer has two essential jobs: separating debris from the pool and regulating the water level. For that purpose, the device sits at the water line, pulling in liquid that drifts in. The moving flap at the poolside hole is called a weir, and its design helps it bring debris in without letting it flow back out. 

Beyond the weir is the basket. The current catches debris and stores it here until someone empties it. Pool owners can access the basket by removing the plastic lid directly above it. These parts work together to keep leaves, insects, and other unwanted items from the water’s surface. 

Underneath the basket, however, are two holes. They sit below the float valve, a regulating tool that measures the pool’s water level to shut off the skimmer when needed. The holes under the float valve are channels that connect to the pool itself and the pump. The float valve is also called a diverter plate since it diverts the water to different locations.

Together, they regulate the pool’s water level consistently. When there is insufficient water in the pool, the system will shut down the pump to prevent it from overheating. If there is too much water, it will feed it back through the pump and into the pool again. By looping the water as needed, the skimmer can facilitate itself and shut down the pump when problems arise.

The Pool Pump Line

Of the two holes in the pool skimmer, the pump line is the one farther from the pool. Only this tube has a vacuum effect, sucking water in from the skimmer. The water that passes through the pump line reaches a filter. There, it is cleaned and reintroduced to the pool. Thanks to that mechanism, a reservoir can continually recycle water and not dry up as easily. 

After being filtered, several return lines send the water back to the pool. The return line exits are all around the walls of your pool guarded by plastic lids or caps to prevent debris from flowing in. Thus, the pool water goes through the skimmer again for filtering and reintroduction. 

If the water level of your pool is too low, the float valve may shut off the pump line entrance in your skimmer. This prevents it from sucking the open air in and running the pump in case it overheats. An overheated pool pump can result in expensive repairs, but the device’s natural cycles help to minimize incidents. 

The Equalizer

The equalizer is the second hole at the bottom of the pool skimmer. It is another contingency measure to keep the pump from running dry, which can cause damage. If not for the equalizer, the pump would suck in air and run continually, even with too low of a water level or a clogged basket.

Here’s how it works. The equalizer hole connects to either the pool drain or an inlet on the wall towards the bottom. When the skimmer doesn’t sense any water coming through the weir, it will draw water from the pool through the equalizer. A clogged basket will cause the same response, so remember to empty the skimmer often.

The water feeds through the pipe, past the float valve, and into the pump line. Keeping the pump from getting dry will avert expensive repairs.

After passing through the pump, the pool water goes through a filter and returns to the main reservoir. Altogether, your swimming pool is a complex system that continually recycles water to preserve the pump’s health. 

Frequently Asked Questions

Now that you know about the holes for the pump line and equalizer, let’s address questions pool owners frequently ask about the mechanism.

Why is one of my skimmer’s holes plugged up?

A plugged skimmer hole only happens when your pool has more than one skimmer. The equalizer is an emergency mechanism that accounts for when the water level is too low. Even a large pool only needs one equalizer line to work properly. 

Pool installers typically use a second skimmer and a small plate to block the equalizer since it’s cheaper than using a separate skimmer model. That’s why they plug one of the holes up. It’s nothing to worry about and is that way by design.

I want to vacuum the pool. Which skimmer hole do I use?

If you’re trying to vacuum a pool, you need to connect the vacuum hose to the pump line hole on the bottom of the skimmer. That’s the hole farthest from the pool on the outer side. If you were to attach the vacuum hose to the equalizer, nothing dangerous would happen. It would fail to work, causing wasted time, effort, and electricity. 

Should I leave the pool skimmer on all the time?

While your pool is running, the skimmer should also run. However, there’s no point in filtering the water within it more than once daily. A general rule of thumb is to turn it on when the pool pump is on and shut it off synchronously. That way, you can be sure that no energy goes to waste while cleaning and using your pool.


Skimmers are fantastic self-maintenance systems that let pools stay healthy and clean for long periods. They filter debris from the water, rid the water of large particles, and serve as a benchmark when the surface level is too low. 

Remembering to empty the basket is essential for your skimmer and pool pump’s health. Keep an eye on it so that you and your kin can enjoy the pool all summer.

The Pool Care Handbook & Video Course

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