How Do I Backwash?

Back(wash) to the Basics

Let's be real, people are gross. And when they get into your pool they can take that gross and spread it around, which then makes everything and everyone else gross as well. Thankfully we have things like pool water disinfectants and filtration systems to protect us from contracting some of the stuff people are capable of spreading around. But over time, your filter gets too full of this gunk and becomes less effective at doing its job. The question is, what can we do in order get the filter back too its maximum performance? The answer is backwashing. But what is backwashing and what does it do? 

In this article we're going to discuss what backwashing is, what it does, how to backwash, and when to do it. 

A Quick Note

Please keep in mind that this article focuses specifically on backwashing a high rate sand filter, which is arguably the most common type of filter on the market. If you have a filter other than high rate sand, click on the words diatomaceous earth or cartridge filtration to learn more about about to perform maintenance on those systems. 

What is backwashing?

Backwashing is a fancy way of saying that we are performing a routine cleaning of our sand filter. During normal operation, our water enters through the top pipe of our filter, shell and pushes that water down through the sand bed inside the filter. As the water travels through the sand bed, the sand itself captures all of, the debris and gunk that makes our water dirty. Essentially, this is how our sand filtration system works.

 But over time that sand can get filled with too much debris, grease and other junk, causing the filter to become less powerful. This is where backwashing comes in. Backwashing is the act of reversing the flow of water through the filter, causing that water to push all the trapped debris up through the top of the sand bed, out of the filter shell, and down the waste line in your pump room.

How Do I Backwash a Sand Filter?

Most sand filters are equipped with a multiport system that allows for backwashing, rinsing, etc. We have actually created a video that shows the steps to backwashing with one of these systems:

When should I backwash?

There is no set schedule to when you should backwash. The gauge at the top of the filter will let you know when it is time. When the pressure rises 8-10 over your normal operating pressure on your pressure gauge, then and only then, will you want to backwash.

How Do I Learn More?

Backwashing a sand filter is only one of the many challenges pool and spa operators face on a day to day basis. This article has given you a good, but brief understanding of one of the aspects of professional swimming pool operation. Thankfully Pool Training Academy offers Certified Pool Operator® courses that will help you become the best aquatics operator you can be. To get signed up for a CPO Certification in your area, please follow this link: Click Here