How to Clean Dirt From the Bottom of a Pool


Even if the water in your pool is clean and sparkling, having dirt on the bottom of the pool just looks awful and unappealing to swim in. So you need to clean it.

The easiest way to clean dirt from the bottom of a pool is to vacuum the pool using a pool vac. If there is lots of dirt then this is best carried out with the multiport valve on waste otherwise it can be done on the filter setting and backwash afterwards to expel any dirt.

You can get dirt on the bottom of your pool a number of ways including the wind blowing it in, children throwing it in or if there is a problem with your DE (diatomaceous earth) filter if you have one instead of a sand filter.

I had quite a bit on the bottom of mine recently after replacing some of the pipework to the skimmers which required lifting the paving and digging out around the pipes.

Step by step guide to removing the dirt in the pool

Step 1 – Brush the pool sides

To ensure any dirt that may be on the sides of the pool is also cleaned it is good practice to go around the pool and brush the sides to allow any dirt to fall to the bottom.

Step 2 – Use a pool net

Use a pool net to carefully pick up as much of the large dirt from the bottom of the pool as possible. This includes leaves, small stones and other debris that may clog up the filter baskets. Small pieces of debris can be left for the vacuum to pick up. Try not to disturb the small particles of dirt too much.

Step 3 – Vacuum on filter or waste?

Choosing which setting to use on the filter multiport valve depends on how much dirt you have at the bottom of the pool.

If there is very little dirt then you can set the valve to filter and jump to step 5.

Multiport Valve Filter Setting
Multiport Valve Filter Setting

If the bottom is very dirty then you should perhaps consider vacuuming on the waste setting. If so then proceed to the next step.

Multiport Valve Waste Setting
Multiport Valve Waste Setting

Step 4 – Top up the pool

When you vacuum the pool on the waste setting the water that is sucked up through the vacuum hose will be expelled from the system. Some pool set ups send the water directly to the sewer system. Others just pump it out of an outlet, perhaps into the garden/yard.

Whichever set up you have, the water level in the pool will go down while you are vacuuming – and quite fast too. So put the hose in the pool and top it right up before you start. This way you may be able to vacuum the whole pool in one go without having to stop and top up halfway through.

Once the pool is topped up continue to the next step.

Step 5 – Connect the vacuum and hose

If the pump is running then switch it off.

Connect one end of the vacuum hose to the vacuum head and lower it into the pool. Feed the rest down into the pool to remove air from the pool hose. This is known as purging the system.

Purging the air out of the hose
Purging the air out of the hose by feeding it in vertically

Now, either connect the vacuum hose to the skimmer, directly into the outlet or using a skimmer vacuum plate or, if you have one, connect to the dedicated vacuuming inlet at the side of the pool.

Step 6 – Switch the pump on

Turn the multiport valve to either filter or waste. If you will be vacuuming on waste then, if you have one, open the valve to the waste outlet so the water can flow out.

Now switch on the pump.

Step 7 – Start to vacuum

You must try to do this as gently as possible to ensure you don’t disturb the dirt on the bottom. Any that you do disturb is likely to go into suspension in the water and will settle again later, meaning you will have to vacuum again.

Vacuuming the pool
Vacuuming the pool – you can see the difference

If you are vacuuming to waste then the temptation will be to try and rush it as you will see the water level dropping while you are cleaning. If you do then you will only have to do it again as you will disturb the dirt so try to resist. If you have to stop half way through and top the pool up then so be it.

When vacuuming on the filter setting you may notice a significant loss of suction. If this happens then this is probably because the filter has become clogged with the dirt. In this case you will need to backwash the filter to clear it and regain the suction.

To backwash a sand filter, switch off the pump, turn the multiport valve to backwash and then switch the pump on again for a few minutes. You should be able to see the dirt and debris swirling in the viewing glass as it is expelled. When this starts to run clear you can switch the pump off and put the multiport valve back to filter before proceeding to vacuum again. For full details on backwashing read my article – How to backwash a pool – a step by step guide

how to clean dirt from the bottom of a pool
Multiport Valve Backwash Setting

Note: If you have a cartridge filter rather than a sand filter then you will have to remove the cartridge filter and clean it manually as they are not built to allow backward water flow so you cannot backwash.

If you lose suction when cleaning on the waste setting then the strainer basket in the pump housing may be blocked with leaves and other debris so you should clean this out. Also, if you are using a skimmer vacuum plate to attach the vacuum hose with the skimmer basket still in place then this may also be blocked with leaves etc.

Step 8 – Finish up

Once all the dirt has been removed, turn off the pump again. Remove the pool hose and lift out the vacuum.

Sand filter pools: Now backwash the filter again by putting the valve to backwash and then running the pump for a few minutes. Then switch off the pump and turn the multiport valve to the rinse setting. Switch on the pump for 30 seconds or so and then switch off. This will settle the sand down again in the filter.

Cartridge filter pools: The filter is likely to be very dirty now so you should remove it and clean it manually before running the pump again.

Put the valve back to the filter setting, switch the pump on and you are done. That is apart from doing the normal maintenance such as checking the chemical levels and adding any as required.

How to remove stones from the bottom of the pool

If you have any stones at the bottom of the pool that are larger than a piece of gravel then you should try to remove them using a net before you start to vacuum.

This is for two reasons:

  • the vacuum may not be strong enough to pick up the stone
  • if the vacuum does then the stone may cause damage to the pool system somewhere

Sometimes they can be very awkward to get into the net as they just get pushed along the bottom. In the past I have sometimes had to resort to diving to the bottom of my pool to pick a stone up.

How to clean the bottom of your pool without a vacuum

This will not be easy and is likely to take a long time, and perhaps more than a few attempts, to get rid of it all as you will inevitably disturb dirt as you clean which will float around and settle on the bottom again later.

Basically you will need to brush the dirt along the bottom using a suitable brush. Use a soft brush if you have a vinyl liner (so you don’t damage it) or a stiffer brush if your pool is tiled or concrete.

You need to brush all the debris into a small pile in one area of the pool. But you MUST do this very slowly. If you do it too fast you will end up stirring the dirt up and some of it will go into suspension in the water and settle elsewhere.

Once you have it in a pile then you can very gently sweep it into a dustpan (perhaps with a long handle) and then slowly lift it out of the pool.

How to prevent dirt getting in the pool

Easier than having to clean dirt out of the pool is taking steps to try and eliminate it getting in the pool in the first place. So try the following to reduce it.

  • Keep the area around the pool clean by sweeping all dust and other debris away regularly
  • Keep pot plants etc away from the pool edges as far as possible
  • Cut back vegetation around the pool
  • If you won’t be using the pool for a while consider fitting a pool cover

My top three pool cleaning tools to make life easier

Dolphin Nautilus CC Plus Robotic Pool Cleaner – the best time saving product on the market. I have never heard anyone say they regret buying one.

Hayward Poolvac Leaf Canister – very useful when leaves are a problem in your pool

Aquatix Pto Pool Step & Corner Vacuum Head – I use this every time I vacuum my pool. It gets where other vacuum heads can’t.

Frequently asked questions

Can you vacuum a pool on backwash?

No, you cannot vacuum on the backwash setting as it reverses the direction of the water flow in the filter so any dirt, dust and debris you vacuum up from the pool will be forced into the bottom of the sand filter.

Can you vacuum a pool on the recirculate setting?

Well yes you can vacuum a pool on the recirculate setting but there is little point. All you would be doing is circulating the dirt around the system and then back into your pool. No dirt would be removed at all.

Why is my pool filter blowing out dirt?

If you notice the sand filter blowing dirt back in pool then this is most likely because the filter needs backwashing if a sand filter (or cleaning if a paper filter). If the filter can no longer cope the debris will just travel back into the pool. It could also be because the multi-valve is set to recirculate so you should check that isn’t the case.

JP in Fuerteventura

I have had hot tubs for many years and a pool for the last 7 years. I had to learn how to clean it, maintain it and fix it the hard way. Since then I have helped many friends and neighbors with their pools and now I want to share everything I have learned with you.

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