Can I Vacuum My Pool on Backwash?




Getting your first pool and learning how to clean it yourself can be pretty confusing at first. Learning how to vacuum correctly and efficiently is probably the most essential thing to learn. So a question many people first have when getting a pool is should I vacuum a pool on backwash or waste or filter?

You can vacuum a pool on backwash, in theory at least, but it would be similar to vacuuming to waste. The water would be pumped backward through the filter before passing through the backwash hose. However, some dirt would be trapped in the filter and then end up in the pool once the pump was back on the filter setting.

I will try to explain why it would not be worthwhile to vacuum on backwash so that you can understand better. You can also read my article How do pool vacuums work?

Can you vacuum a pool on backwash?
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Why shouldn’t you vacuum on backwash?

This is because when the multiport valve is in the backwash setting, the water flows from the pump into the bottom of the sand filter rather than into the top as it usually does.

When you run the filter on backwash, the water passes through the sand or filter medium from the bottom, picking up trapped debris as it goes, and then expels the water containing the debris out of the waste pipe into the yard, down the drain or wherever your pool expels water to.

If you were to vacuum a pool on backwash, all of the dirt you pick up from the pool would get pushed through the layers of the sand before being expelled out of the system.

Some debris would inevitably get trapped in the bottom of the filter. Then, when you had finished vacuuming and put the multiport valve back into the filter, much of that dirt that had become trapped in the bottom of the sand filter would be pumped back into the pool. This would rather defeat the object of vacuuming the pool in the first place.

So, vacuuming on backwash would have a similar effect to vacuuming on the waste setting of the multiport valve as the water containing the dirt and debris would be expelled from the pool system without going back into the pool. But it would add a pointless step with the water having to pass through the filter medium before being expelled from the system.

See my post Where does backwash water go for more information.

Can you vacuum a pool on backwash?

What setting should my pool pump be on to vacuum?

There are only two settings on the multiport valve to use to vacuum a pool and which one you would use largely depends on how dirty the pool is.

Vacuum a pool on filter setting

This is the setting you will use most frequently. You would vacuum in this setting for your routine cleaning when the pool is not very dirty. When you use this setting, the dirt is trapped in the sand or whatever filter medium you have, and clean water returns to the pool via the return jets.

You would often backwash the filter for a few minutes to clean out this dirt before returning to the filter setting.

Vacuum a pool on waste setting

You would generally only use this setting if the pool is very dirty, perhaps when you do the first clean of the year after the winter or if you had a period of very bad weather when lots of debris ended up in the pool. When to vacuum a pool to waste.

See my complete guide How to vacuum a pool to waste to learn how to actually do it.

Read: My pick of the best pool vacuum heads

Can you backwash a pool while vacuuming?

I sometimes have to stop while vacuuming my pool on the filter setting (so the water passes through the sand filter) because the suction begins to reduce. This is due to the sand in the filter becoming clogged, which reduces the amount of water that can pass through the sand, increasing the back pressure.

You can often tell if this is the problem as the reading on the pressure gauge is likely to be higher than usual because of it.

To restore the suction, I switch off the pump and then move the multiport valve to the backwash setting. I then run the pump again for a few minutes to remove the dirt blocking the sand and resume vacuuming once I put the multiport valve back to the filter setting.

I leave the vacuum hose connected to the skimmer port while I do this so no air gets into the system and I can resume vacuuming straight away after the backwash. Read my full step-by-step backwash guide for further details.

Do you vacuum a pool on backwash or waste?

You should vacuum a pool on “waste” when dealing with a significant amount of debris, algae, or dirt you don’t want to pass through your filter system. Vacuuming on “waste” bypasses the filter and sends the water directly out of the pool, preventing contaminants from clogging or passing through the filter.

The backwash setting is used to clean the filter, not to vacuum the pool.

The normal setting to vacuum a pool is the filter setting.

Should I Backwash After Vacuuming Pool

After vacuuming the pool, it is recommended to backwash a sand filter system, particularly if the pool was quite dirty.

Backwashing involves reversing the water flow through the filter to remove any debris and contaminants trapped during the vacuuming process. Backwashing is an important part of keeping the filter system in good condition.

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Cleaning a pool can be confusing, especially when considering the order of actions like backwashing and vacuuming. So, should you backwash a pool before or after vacuuming?

Firstly, let’s address the question, “do you backwash a pool after vacuuming?”. The answer is not definitive and depends on the circumstances. If there is excessive debris or dirt in the pool, it is advisable to vacuum the pool on waste or backwash. This lets you remove the debris directly from the pool without passing it through the filter. Vacuuming on waste or backwash prevents clogging of the filter and ensures efficient cleaning.

However, if there is only minimal debris in the pool, it might be sufficient to vacuum it on the regular setting without resorting to backwashing. In such cases, backwashing after vacuuming can be unnecessary.

Another related query is, “can you vacuum a pool on backwash?” Technically, it is possible to vacuum a pool on backwash, but it is not the recommended method. Backwashing primarily cleans the pool filter by reversing the water flow and flushing out trapped debris. Vacuuming on backwash can potentially damage the filter system and is ineffective for cleaning the pool.

To summarize, it is best to vacuum a pool on waste or backwash when a significant amount of debris is present. However, for routine cleaning with minimal debris, vacuuming on the regular setting is sufficient, and backwashing may not be necessary. Remember to assess the condition of your pool and adjust your cleaning routine accordingly to maintain its cleanliness and functionality.

Further Articles

You may find the following articles helpful, particularly if you are a new pool owner. I try to answer most of the questions I had when I first bought my house, which came with an in-ground pool with a sand filter system.

How to remove air from a pool vacuum hose

How to bleed air from a pool pump

How often should I vacuum my pool?

Why are there two holes at the bottom of a skimmer?

Best way to get leaves out of a pool

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