3 Ways How To Adjust Pool Skimmer Suction

green pool tile and lounge chairs in backyard pool setting

If you have a heavy debris load in your pool, you are constantly looking for ways to reduce the amount of debris you need to pick up off the floor.  A great pool cleaner will go a long way when it comes to removing the leaves. Wouldn’t it be easier if the leaves never sank to the bottom in the first place?  Wouldn’t it be great if your skimmers did more of the surface cleaning before anything sank to the bottom?  In many cases all you need is some adjustment of your skimmers.  In this article we will go over the common methods for how to adjust pool skimmer suction.

How To Adjust Pool Skimmer Suction

There are multiple ways to adjust pool skimmer suction because there are multiple ways you can plumb a pool.  There even is disagreement among professionals about which type of valves to use, how to plumb skimmers, and so on.  

How To Adjust Pool Skimmer Suction With A Two Hole Skimmer

If you have a two hole skimmer and notice both holes are not plugged, you might try plugging the front hole to restrict flow from the main drains. When you have a two hole skimmer and both holes are being used, that usually means your main drains are plumbed up to the bottom of the skimmer. This reduces the flow rate over the skimmer weir, and reduces the skimmers reach.  When adjusting a pool skimmer, it’s all about increasing the reach of the skimmer into the pool.

If your skimmer is a single hole, or a two hole with one of the holes plugged, you likely have a control valve back at the pool equipment.  Furthermore, when you’re lucky, these valves will be labeled.  If not, here’s some visual aids which hopefully will help.

How To Adjust 3-Way Valve Pool Skimmer Suction

In the photo below, you can see the cream colored pump, with a pipe extending out from the front of it going into a black 3-way valve.

Pool Equipment Set Showing How To Adjust Pool Skimmer Suction With 2 Way Valve In Backyard With Red Brick Wall Behind

There are two pipes coming out of either side of the 3-way valve.  One of those pipes goes to the main drains, and one of those pipes goes to the skimmer or skimmers.  First, you want to determine which of these pipes is the skimmers.  If one of the pipes is smaller than the other, most likely the smaller pipe is the skimmers. 

Turn the valve so the “off” label is pointing to the smaller pipe. Only afterward should you then turn the pump on.  Walk over to the skimmer and make sure the skimmer is off.  Now you know which pipe is which. Grab a sharpie and write right on the pipe ‘skimmer’ and ‘main drain’ on the other.  

How To Adjust 2-Way Valve Pool Skimmer Suction

In this photo you can see the pipe coming out of the pump extending to a manifold with four individually valved pipes:

Pool Equipment Set Showing How To Adjust Pool Skimmer Suction With 3 Way Valve In Backyard With Green Shrub Behind It And Stone Walkway In Front

With pools plumbed like this, you can control flow from every pipe individually.  However, the experimenting can be a bit more dangerous. This is because there’s the ability to ‘dead head’ the pump.  To ‘dead head’ the pump means you could shut off all the valves, turn on the pump and the pump would have no source of flow.  In this case you need to experiment with each of the valves and by the process of elimination determine which pipes are from the main drains, which are from the skimmers, which are from the spa main drains (if you have a spa) and so on.  

Label the pipes as you determine which are which.  Once you’ve identified the pipes, you can explore how much restriction you can place on your main drain pipe and still provide adequate flow to the pump.  This will maximize the suction from your skimmers.

How To Adjust Pool Skimmer Suction Summary

We are often surprised at the creativity of pool builders and the way they plumb swimming pools.  Especially pools built long ago.  It’s not a bad idea to hire a pool professional to assess your equipment set. They can determine whether or not there are safety issues or reasons you should consider replacing main drain covers, pumps, and/or filters.  Whenever this work is being done, it’s a good time to revisit how the equipment is plumbed, and how it is valved.