Should I Use My Pool Main Drain Or Skimmers?

Pool Skimmer

Great pool circulation is the bedrock of having an excellent swimming pool with healthy and clean water. But where will I get the best circulation? Should I use the Main Drain or Skimmers?

You should use both your main drain and skimmers for your swimming pool anytime it is in operation. Skimmers pull and move water from the very top of the pool while the main drain located at the lowest point in your pool sucks water from the area that the skimmers can’t circulate. Running both the skimmers and main drain to cycle your pool is hands down the best way to keep a healthy, balanced, and safe swimming pool!

If you want to understand a bit more about the circulation being provided, I’m going to jump into some deeper information about how the skimmers and main drain circulate your swimming pool water. We will also discuss when you should be switching the valve settings to apply more suction to the skimmers or the main drain.

The Benefits of Using Both your Skimmers and Main Drain at the Same Time

The amount of water that you can pull into your filter will greatly increase when you use both your main drain and your skimmers. This will lower the turnover rate time for all of the water in your pool to circulate through your filter. For example, if you ran only your skimmers it might take 6-8 hours for your pool to circulate all of the water in your pool through the filter. If you add your main drain into the mix, you could perhaps reduce that time to 3-5 hours. This would increase the number of times per day that your water would get a chance to process through your filtration system. 

To keep a clean and well-balanced pool you want your swimming pool water turnover rate to be as quick as possible so running both the skimmers and main drain will give your the maximum potential to reduce your turnover rate time.

The skimmers and main drain also focus on circulating the swimming pool water in different areas of the pool. This will reduce the number of dead spots, and areas where the water isn’t circulating, to keep your pool clean. Manual time spent cleaning, scrubbing, and pulling debris from your pool is less if you reduce your dead spots. Sometimes you will always get this in a pool and it is unavoidable but having skimmers and the main drain operating in unison will give you a better chance as a pool owner. 

Can I Run my Pool with Only a Main drain or Only my Skimmers?

Yes, you could operate your pool only using your main drain or only using your skimmer. But as mentioned in the above section it isn’t recommended as it will reduce your swimming pool water circulation. 

If you chose to only operate your main drain, you will need to spend a lot of time manually cleaning the surface water of your pool. Only operating the main drain will also only circulate the water from the deepest part of your pool. The main drain ideally should be pulling in ⅓ of your pool water into your swimming pool water turnover. If you force it into pulling 100% of your turnover you’ll see a reduction in the quality of your pool water. 

You can operate your pool with only skimmers, and many above-ground pools do this but it isn’t my recommendation here at Cool Pool Help. The skimmers do exactly what their name suggests which is to skim the surface of the water from debris. They will pull in leaves, bugs, and all the debris that can collect on the surface of your pool water. The skimmers also generate that circulation on the walls of your pool by sucking in water which keeps that nice water rotation near the surface which will bring up debris from inside the water in your pool.

In my opinion, the only reason to be operating using only your skimmers or only your main drain is if one of the above is damaged. To prevent such things from happening, be sure to blow out your main drain and skimmer lines every winter when closing your pool. If are having a leak or clog and need to operate using only one, go right ahead. You will be totally fine while you are sorting out repairs or unclogging the issue.

Will operating both the main drain and skimmers cost more?

No, operating the main drain and skimmers will not add to your bills in any way. Actually, having both the main drain and the skimmers operating together can actually save you a bit of money each year on pool chemicals. It may not be a huge amount each year that you save, but if you add that up over the lifespan of your pool and the savings really justify operating both the skimmer and main drain.

Should I run both the skimmer and Main drain at 100% open?

You absolutely can do this, and it is often the recommendation from your pool builder. In my experience, though each pool system ends up functioning a bit differently over time with a bit of age. As I’ve mentioned in other articles on this site, you should really begin to play with the valve openings on your skimmer and main drain in your first season with your pool. You’ll be able to find out what balance between the skimmer pull and the main drain pull works best for your unique pool.

Consistently online you will hear that those who open their main drain up close to 100% see quite a loss of pulling power from their skimmers. I don’t really find this to be a problem personally because I don’t want my skimmers to do all of the heavy liftings. I want to keep a nice circulation going in my pool from both the main drain and the skimmer at the same time. So it would be natural that my skimmers aren’t chugging along at maximum power because they are getting ⅓ of their circulation from my main drain. I might need to skim the top of my pool with a net a bit more often but that manual labor spent is less of a concern to me than the balance and safety of the pool water as a whole.

I’ve read online from some pool owners who choose to operate their skimmers 100% open with their main drain consistently at 10%-20% open. This works for them and if their pool is remaining clean and balanced then they should stick with that setting each year. Other pool owners find that 80% open from the main drain is great for them. You’ll just have to work your valves to see which settings work best for your pool. You can check out more about this topic here in our article, should my pool main drain be opened or closed?

When Should I Adjust the Suction from Skimmers or Main Drain?

All of us pool owners have been in this situation before, we have some people coming over for a bbq or party and need to get the pool ready. We take a lookout and we see a clean pool with some debris floating around. What should we do?

Head on over to your valve settings, reduce the power to your main drain, and make sure your skimmers are completely open. This will pull a lot of that debris toward the skimmer if not into the skimmer making for easy cleanup. If you have a home that is surrounded by trees, you might want to operate with a higher pull on your skimmers consistently to keep the surface of your pool clean. 

If you notice the debris and sediment in your pool are heavy on the bottom, then we want to do the opposite of what is suggested above. Head on over the valve and turn up your main drain to 100% to pull that debris into the catch of the main drain. After a few hours of running with a 100% open main drain, most of the sediment should begin to collect near the main drain. This makes jumping in manually to spot the vacuum really simple and quick. If you consistently see an issue like this, You might want to check and see if your main drain is working or not.


The founder of I wanted a place to share all of the great information from my family to other pool lovers, builders, and those looking to buy a pool.

Recent Posts