Adjusting Pool Skimmer Suction: A DIY Guide for Homeowners

Unfortunately, swimming pools don’t keep themselves clean; they require regular maintenance. One of the parts you need to keep your eye on is the pool skimmer, which removes debris and other contaminants from the water’s surface. Adjusting the pool skimmer’s suction may occasionally be necessary to ensure your pool stays clean and healthy.

Before you adjust the pool skimmer suction, you should establish your pool’s ideal flow rate. A diverter plate inside the skimmer or on the valve float easily adjusts the skimmer suction. The suction levels can also be affected by blockages in the skimmer line. Unclogging the pipes will help.

Explore more reasons why your pool skimmer may not be working well.

Your pool skimmer’s performance directly affects the health of your pool, and incorrect suction rates can also impact your pool equipment negatively. Fortunately, it’s not difficult to adjust the skimmer’s suction. Read on to find out the details on why this is necessary and how to do it.

How To Adjust Pool Skimmer Suction

Before we dive into how to adjust the skimmer suction, let’s briefly examine how a pool skimmer works.

Pool skimmers are usually found on the sides of the pool and have a small flap, the weir, that opens and closes to allow water to flow into the skimmer. The weir improves water flow and efficiency.

When the water enters the skimmer, it passes through a basket that catches leaves, bugs, and other debris. From there, it travels to the pool’s filtration system, where it is cleaned and then returns to the pool.

There are a few circumstances when you might need to adjust the skimmer suction, including:

  • The suction is too low when the skimmer isn’t collecting dirt and debris as effectively as it should.
  • High suction causes the skimmer basket to fill up too quickly, putting the pump at risk.
  • Improper water flow

Adjusting The Suction

The ideal skimmer suction will depend on the size of the pool, the pump’s horsepower, and the type of skimmer. A flow rate of 30-50 gallons per minute (GPM) is ideal. How do you know your pool’s flow rate? You can use a flow rate meter or check the specifications in the manufacturer’s manual. Many variables affect a pump’s flow rate, so installing a meter on the pump makes life easier.

Adjusting The Suction Using The Diverter Plate

The skimmer plays a significant role in keeping your pool clean by filtering the water. A diverter plate allows you to decide whether this water goes to the pump or the main drain.

Once you’ve established your ideal flow rate, you can adjust the skimmer suction. Start by removing the skimmer basket and find the two holes in the skimmer box base that lead to the pool pump and the main drain.

Position the skimmer diverter plate over these two openings, ensuring you keep your fingers on the plate and away from the holes. If you want to divert all suction to the pool skimmer, rotate the diverter plate until the nipple faces away from your pool. This setting is suitable for pools that typically have a lot of debris floating on the surface.

If you need to direct the suction to the main drain, turn the nipple towards the pool. You can use this setting if your pool tends to collect more dirt in the water than on the surface.

Rotating the diverter plate so the nipple is between these settings directs suction to both the pump and the main drain.

Improper skimmer suction can contribute to issues like cloudy pool water. Find out what to do when your pool water is cloudy.

Automatic Suction Adjustment With The Float Valve

If your pool level drops below the skimmer’s mouth or the basket is blocked with debris, preventing the water from passing through, the float valve automatically closes over the two ports. This directs all water from the main drain to the pump, preventing air locks from forming.

When the pump is turned off or the water level rises again, the float valve returns to its original position, and the process starts again.

Adjusting The Jets To Increase The Flow To The Skimmer

Once the water has traveled through the filtration system via the pool skimmer, the return jets push it back into the pool. To increase the flow toward the skimmer, you can change the angle of the jets. This allows more water to flow into the pool skimmer, increasing filtration. Follow these steps to adjust the jets:

  1. Switch off the pool filter, and if your pool is connected to an electrical system, do the same with the pool circuit breakers. This causes the jets to stop pumping, making it easier to adjust them.
  2. Find the pool jets inside the pool (you might have to go underwater), and move the tip so that it points toward the closest skimmer.
  3. Repeat for each jet.

Tips For Keeping Pool Skimmer Suction Stable

Although it’s easy to adjust the pool skimmer suction with a diverter plate and valve float, other issues sometimes cause a loss of suction. Watch out for these issues that can affect your flow rate and suction.

Check For Clogs

Clean the skimmer basket out regularly, especially if your pool collects a lot of surface debris. Water can’t pass through the system if the skimmer basket gets clogged.

The skimmer line may be blocked, and signs of this can include the following:

  • A pulsing or loud pool pump can indicate the skimmer pipe is blocked. If you’ve ruled out other possibilities, such as a clogged pump impeller, air leaks, or a dirty filter, you may well have a clogged skimmer line.
  • An airlock might have formed if you’ve recently cleaned the pool filter.

To sort these issues out, switch off the pool pump, remove the lid and basket, and push a hose inside the pipe. Blast some water through the line. It should get rid of any blockages or airlocks.

If you’re unsure which line is blocked, check each one individually using the Jandy Valve, always leaving one line open. Move the Jandy back and forth between the settings for a few seconds each time. This could get rid of the airlock or stuck debris.

Ensure The Water Level Is Correct

Always fill your pull to approximately halfway up the skimmer box mouth for the ideal suction rate. If the water is too low, your skimmer could suffer severe damage, and the pump motor could burn out. If the level is too high, the flow will slow or stop debris from flowing into the skimmer, leaving your pool with dirt floating on the surface.

Check That The Weir Is Working Correctly

The weir opens and closes to let water into the skimmer. If the weir is stuck in the closed position or misaligned, it can prevent water from flowing into the skimmer, leaving debris and dirt in the pool.


Various situations may demand that you adjust the pool skimmer suction. It may be a simple matter of diverting the flow between the skimmer and the main drain with a skimmer diverter plate during regular pool maintenance. Or sometimes, skimmer lines and other issues require fixes that reset the correct flow. Pool health rests heavily on the skimmer, so ensure that it always operates correctly.