Too Much Flocculant

I Put Too Much Flocculant In My Pool - What Should I Do?

Pool flocculants are powerful coagulant chemicals that cause tiny particles of debris in your pool to stick together and form heavy clumps. These clumps then sink to the bottom of your pool where they must be removed by vacuuming in order to restore your pool’s clarity.

Can you accidentally add too much flocculant to your pool? What happens if you do?

In this article we will discuss what happens in your pool when you add too much flocculant, as well as what steps you can take to remove any excess flocculant.

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Effects of Using Too Much Flocculant

When too much flocculant is added to pool water, it often fails to work.

In high concentrations, the active ingredient in your flocculant, which is typically aluminium sulphate, is more prone to stick to itself rather than the debris in your pool. This results in your pool water staying murky, and also adds additional debris that needs to be cleaned up.

You may notice some clumps of coagulated flocculant in your pool, but these are unlikely to have captured much debris and may also fail to sink to the bottom.

How to Remove Excess Flocculant

Just because your flocculant has not worked as intended does not mean that it can be removed by your filter system. Failed attempts at using a flocculant take special care to clean up, because any flocculant that ends up in your filter could cause damage or clogs.

Step 1 - Ensure Pump Is Set To Off Or Recirculation

While cleaning up excess flocculant, you should leave your pump shut off unless you are able to choose a recirculation setting that bypasses the filter.

Step 2 - Use Dip Net To Remove Floating Clumps

To begin removing excess flocculant from your pool, we recommend using a dip net. To the best of your ability, remove as many floating large clumps of debris or coagulated flocculant as you are able.

Step 3 - Vacuum Settled Debris On Pool Base

Afterwards, you will want to vacuum your pool if any of the product or debris has settled to the bottom. Make sure you vacuum your pool to waste, and do not let any flocculant pass through the filter.

Step 4 - Partially Drain & Refill Pool

Once you have netted out any noticeable clumps and vacuumed larger debris, you should perform a water change on your pool.

We recommend exchanging around 10% of your pool’s total volume with fresh source water. In a pool of 50,000 litres, this would be equivalent to 5,000 litres, but you may opt to do a larger amount if you suspect that your problem is severe.

Draining and partially refilling your pool removes a large amount of the flocculant you have added while also clearing up some of the particles of debris.

Diluting your pool’s water can also allow the flocculant that is remaining in the pool to behave more normally, capturing debris as intended.

Make sure your pump is running on a filter bypass setting as you refill your pool in order to keep the water circulated. After this is complete, shut the pump off entirely.

Step 5 - Allow Water To Stand

After performing a partial water change, you should then allow your pool to rest for the amount of time originally indicated on your flocculant’s packaging. This allows remaining amounts of flocculant in your pool the chance to bond properly to debris and settle to the bottom.

Step 6 - Use Dip Net & Vacuum Again

At this point, your water’s clarity should be at least somewhat restored. Vacuum up the flocculated debris that accumulated on the bottom of your pool after the waiting period.

If you notice any large clumps floating, remove them with a dip net. After all large particles of flocculant are removed, you may turn your pump back on and resume filter operation.

Step 7 - Run Filter As Normal But Watch Pressure

Because it is possible that some flocculant will be left in your pool at this time, we recommend keeping an eye on your filter, particularly the pressure drop, and cleaning it as necessary.

It is a good idea to manually clean or backwash your filter after it has been circulating flocculated water for a few hours to remove any potential clogs from your equipment.


Yes, you can add too much flocculant to your pool and it will cause problems. Too much of a good thing is not always a good thing.

Flocculant tends to become completely inactive when used in too high of a dose, causing even more of a mess for you to clean, along with a lot of extra hassle.

Do you have any questions about what to do if you add too much flocculant? Drop a question in the comments, we’d love to help you out!

Louis from Pool Advisor


A chemical engineer by trade, Louis is committed to debunking myths in the pool industry by explaining the underlying chemistry and making it accessible to all.