How Does A Pool Skimmer Work?


Why Is My Salt Water Pool Liner Slippery? (Or Slimy)

A pool skimmer serves a few important purposes for pool owners and is part of the filtration system connected through the pump. In addition to skimming leaves, bugs and other debris off the top of the pool, it is also typically the place where pool owners attach their hose to vacuum the pool every week. Since it operates only with the pump running, the skimmer also returns water from the pool to be rechlorinated and cleaned.

What Does A Pool Skimmer Do?

The skimmer operates in conjunction with the pool pump which tends to draw water from two sources: The skimmer which is at the side of the pool usually in the deep end, and the main drain which is located at the very bottom of the pool in the deepest part. That way water is being drawn from both the top and bottom of the pool. When the pump is shut off, the skimmer doesn’t work.

As mentioned above the skimmer provides three main purposes for most pool owners.

Removing a pool skimmer basket to empty the leaves out
The skimmer is located at the side of the pool. Here we see the inside view with the lid removed and a skimmer basket full of leaves and debris.

Skims The Top Of The Pool

The skimmer as the name would suggest skims the top of the pool and pulls debris from the pool surface towards it through pump suction and collects it in the skimmer basket. Typically, leaves, twigs, pollen and anything else that collects on the pool water surface can make its way to the skimmer.

The skimmer is designed to draw water from the top of pool and works best when the return jets inside the pool are pointed downwards. This ensures a flat, consistent flow of water into the skimmer, water turnover is greater and the skim time required to clean the top of the water is reduced.

Returns Water For Cleaning

The skimmer is attached to the pump through underground piping. The pump draws water in from the skimmer through the pipes back towards the pump. The water passes through the filter to be cleaned and then passes through the chlorinator salt cell to convert salt to new chlorine. The water is then returned through the piping out through the return jets back inside the pool.

Provides Suction For Vacuuming

Many pool owners also used the skimmer for vacuuming the pool. The lid and skimmer basket of the skimmer are removed and the pool hose is inserted into the hole in the skimmer. The suction from the pump is then transferred to the hose which is then able to vacuum the pool with a vacuum attachment at the other end of the hose.

If you have a robotic vacuum cleaner with an independent motor it’s likely that it only requires being plugged into an electrical socket and works independently of the skimmer.

Parts Of The Skimmer

Skimmer Lid

The skimmer lid is a plastic top that covers the skimmer opening and can be walked upon and prevents people from tripping and falling in.

Weir

The skimmer weir is the flapping door that opens and closes with water flow. It exists to let water in but prevent debris from the skimmer from entering and then coming back out again. This works whether or not the pump is switched on as waves from the pool will open and close the weir.

The weir can get stuck open if something jams it and given the weir design, it is possible for water to be prevented from entering it and the pump will start sucking air. It hasn’t happened to me often but it has happened.

Skimmer Basket

The skimmer basket has small holes throughout so it lets water through but holds debris like leaves, twigs, bugs, etc and won’t let them through. Every day or so depending on how dirty your pool gets you empty the skimmer to keep it from getting packed. After not checking it for a few days or after a heavy rain storm, I’ve emptied the skimmer basket with perhaps a pound of stuff in it. Wet leaves get quite heavy…

Skimmer Tube and Piping

The skimmer has an opening that is big enough to fit the end of a standard pool hose in it. Pool pipes are typically 1.5″ or 2.0″ in diameter and are made of PVC. So water enters the opening of the skimmer and is sucked in through the piping by the pump and then enters the filter and chlorinator salt cell.

Conclusion

The skimmer serves three main purposes as described above related to filtration, cleaning and vacuuming. It’s best to check the skimmer basket daily if possible especially if you have a yard full of trees, shrubs, plants etc and after heavy wind or rain. You’d be surprised at how heavy the basket can get full of wet leaves and debris.

Carl Mueller

I bought a home with a salt water pool in 2006 and soon realized the benefits over traditional chlorinated pools. On this website I'll discuss all the tips and tricks I've learned over the years. I'll also help you troubleshoot various problems with pools in general and ones specific to salt water pools that I've experienced personally!

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