When to Use Flocculant

With warm temperatures coming taking care of pool water becomes more of a challenge even if you do everything right chances are your pool will turn cloudy or even green with algae after a long hot weekend of several days of rainstorms. Clarifiers can keep pool water clear. When should I use a pool flocculant?

Use a pool flocculant:

  • During severe cloudiness(suspended particles too small for the filter to capture)
  • After algae blooms
  • After heavy pool use in the summer months (pool party)
  • Following rainstorms
  • Removing metal stains(iron or copper)
  • High TDS or murky levels
  • Post-construction
  • Special events prep

Pool flocculant settles bigger suspended particles, dead algae, and non-living organic contaminants and by breaking the surface tension of the pool water, these particles settle on the pool bottom allowing them to be vacuumed around the filter media and out to waste.

When Should I Use Pool Flocculant


Flocculant chemicals are a great way to clear up your pool quickly, but you should only use a Floc pool chemical when you have some extra time to slowly vacuum well after it has clumped everything together.

A clarifier clumps the particles together so that a sand filter can pick them up and clear them from pool water. This takes a bit longer to get the pool clear but will work given the right dosage usually following the shock process. During summer months you should be Super-Chlorinating and then adding a Clarifier to help the filtering process.

Cloudy Pool After Rain? - In The Swim Pool Blog
Flocculants for Cloudy Pool

Pool flocculant is a chemical used in swimming pool maintenance to help remove suspended particles from the water. Here are some situations when you might consider using pool flocculant:

  1. Cloudy Water: If your pool water appears cloudy or murky despite regular filtration and chemical treatments, it may be due to suspended particles that are too small for the filter to capture. Flocculants can help clump these particles together, making them easier to remove.
  2. Algae Bloom: In cases of algae bloom, where the water turns green due to algae growth, flocculant can help to gather the algae cells together for more effective removal by filtration or vacuuming.
  3. Metal Stains: If your pool water has metal stains, such as from iron or copper, flocculant can help to gather these particles together, making it easier to remove the stains and prevent further discoloration of the water.
  4. After Heavy Pool Use: After a period of heavy pool use, such as a pool party, the water may become cloudy due to an accumulation of oils, lotions, and other organic debris. Flocculants can aid in clearing up the water by clumping together these contaminants for removal.
  5. Post-Rainstorm: After a heavy rainstorm, debris, dirt, and other contaminants can wash into the pool, leading to cloudy water. Flocculants can help to clear up the water by gathering these particles together, allowing for easier removal through filtration or vacuuming.

It’s important to note that while pool flocculant can be effective in clearing up cloudy water and removing suspended particles, it should be used judiciously and according to the manufacturer’s instructions. Overuse of flocculants can lead to over-concentration of particles and difficulty in filtration. Additionally, after using flocculant, it’s essential to follow up with proper filtration and cleaning procedures to remove the clumped particles from the water effectively.

A Flocculant will clump the particles into larger clumps and sink them to the bottom to be vacuumed up. You should vac to waste if a floc is what you used as it will clog your filter. The clumps can break up, so we’d recommend vacuuming very slowly to not break them up.

If your swimming pool is just a little cloudy, I recommend using a pool clarifier first to see if that does the trick. With a clarifier, you can still swim while it’s working, but you will probably have to wait longer, maybe a few days to see the results.

The cloudiness is likely the dead algae you’ve managed to kill with shock treatments. If you’re alkalinity and pH are where they need to be you should be able to effectively maintain Chlorine and the Flocculant chemicals should be successful.

Even shock chlorine will cloud up your pool water with inert ingredients and fillers that are added to the best-quality pool product. After shocking adding a Clarifier should be all you need after a weekly summer shock. A flocculant should be used only when the balance and control are lost because of

  • pool usage
  • rain storms
  • heat
  • chemical imbalance issues
  • lack of maintenance issues
  • bad pool chemicals

What is Pool Flocculant?

A pool flocculant is a chemical that helps to remove small particles from pool water, these particles can include dirt, debris, algae, and bacteria. Flocculants work by clumping these particles together helping them settle out so that they can be removed from the pool H2O by vacuuming ……………………………………………. Read more


  1. High TDS (Total Dissolved Solids) Levels: If your pool water has high levels of dissolved solids, which can cause cloudiness and affect water balance, flocculant can help to gather these particles together for removal, thus improving water clarity and quality.
  2. Residual Chemical Buildup: Sometimes, residual chemicals from previous treatments can accumulate in the water, leading to cloudiness or other water quality issues. Flocculants can aid in gathering these residual chemicals for removal, allowing for better water clarity and balance.
  3. Post-Construction or Renovation: After pool construction or renovation work, such as plastering or tile installation, fine particles and debris may be left in the water, causing cloudiness. Flocculants can assist in clearing up the water by clumping together these particles for easier removal.
  4. Before Special Events: If you’re preparing your pool for a special event or occasion where water clarity is particularly important, such as a wedding or photoshoot, using flocculant can help to achieve sparkling clear water for aesthetic purposes.
  5. Routine Maintenance: Some pool owners incorporate the use of flocculant into their routine maintenance schedule to ensure consistently clear and balanced water. Periodically using flocculants can help prevent the buildup of small particles and contaminants that could lead to cloudy water over time.


How To Clear Up A Cloudy Pool - How To Use Flock - Flocculant - YouTube

What is Flocculant

Flocculant, in the realm of swimming pool maintenance, is a chemical solution designed to address water clarity issues by aiding in the removal of suspended particles. These particles, often too small for conventional filtration systems to capture effectively, can lead to cloudy or murky water, diminishing the overall aesthetic appeal and potentially compromising swimmer comfort.

Flocculants work by causing these tiny particles to clump together, forming larger masses that are more easily trapped by the pool’s filtration system or sink to the bottom where they can be vacuumed out.

This process results in clearer, cleaner water, enhancing both the visual appeal of the pool and the effectiveness of chemical treatments. However, it’s crucial to exercise caution and follow recommended dosages, as overuse of flocculant can lead to complications such as clogging of filters or difficulty maintaining chemical balance. When used appropriately, flocculants can be a valuable tool in maintaining optimal water quality in swimming pools.

Remember to always follow the manufacturer’s instructions when using pool flocculant, and test the water regularly to maintain proper chemical balance and clarity. Additionally, ensure that your filtration system is functioning correctly to effectively remove the clumped particles from the water after using flocculant.

Either way, there’s always a way to get your water crystal clear like keeping your pool water chemically balanced, maintaining proper pH and free chlorine levels, and finding the right product and deciding how long you can wait to get results. Once the pool water has turned for the worse it’s a step-by-step process to get it back.

If your pool falls out of control you’ll know the signs when it happens:

  • Cloudy pool water (milky color water)
  • Green color pool water
  • pH, Chlorine, Total Dissolve Solids, and Alkalinity (TA) tests become skewed

A Flocculant, or pool floc as it’s sometimes called, is a chemical that you add to your pool when other methods of clearing it up aren’t working. It is used after the fact after you lose control of your pool’s stability and balance when algae and microbes take over and clarifiers and other chemicals won’t cut it.

Flocculants shouldn’t be used all the time. It won’t balance your pool’s chemistry or kill the algae in the pool water and it may clog your filter if you don’t wait long enough. Be patient. When you need a quick solution to pool water cloudiness but it does not fix the reason for the cloudiness and breakdown of the pool water’s condition!

When to Use a Clarifier Instead of Flocculants

Knowing when to use a clarifier instead of flocculants depends on the specific needs of your pool and the type of particulate matter causing water clarity issues. Here are scenarios where a clarifier might be more suitable:

  1. Mild Cloudiness: If your pool water is only slightly cloudy or hazy, a clarifier can help to improve water clarity by coagulating small particles without causing them to settle to the bottom quickly. Clarifiers work by binding smaller particles together to form larger clumps that can be caught by the pool filter more efficiently.
  2. Ongoing Maintenance: Clarifiers are often used as part of regular pool maintenance to prevent the accumulation of small particles that can lead to cloudy water over time. They help to maintain water clarity between regular filtration cycles and chemical treatments.
  3. Routine Use: If you prefer a proactive approach to water maintenance, using a clarifier regularly, such as weekly or bi-weekly, can help to keep your pool water consistently clear and sparkling by preventing the buildup of fine particles.
  4. Preventing Scale Formation: Some clarifiers also contain ingredients that can help prevent the formation of scale on pool surfaces and equipment, making them beneficial for pools prone to scaling issues.
  5. Compatible with Sand Filters: Clarifiers are generally safe to use with sand filters, as they do not typically cause the rapid clumping of particles that can lead to clogging. This makes them suitable for ongoing use without the need for frequent filter backwashing.

In contrast, flocculants are best suited for more severe cases of cloudy water or when you need to quickly clear up the water for a specific event or occasion. Flocculants cause suspended particles to clump together rapidly, leading to their rapid settlement at the bottom of the pool, where they can be vacuumed out. This process is effective for quickly clearing severely cloudy water but may require more effort to remove the settled particles from the pool.

Ultimately, the decision to use a clarifier or flocculant depends on the specific circumstances of your pool and your preferences for water maintenance. If you’re unsure which product is best for your situation, consult with a pool maintenance professional for personalized advice.


In conclusion, flocculant plays a crucial role in maintaining the clarity and cleanliness of swimming pool water. By effectively clumping together suspended particles, flocculants facilitate their removal through filtration or sinking, resulting in clearer and more visually appealing water. However, it’s essential to use flocculant judiciously, following manufacturer guidelines, to avoid potential issues such as filter clogging or chemical imbalance. When used correctly, flocculants can contribute significantly to the overall enjoyment and maintenance of a swimming pool, ensuring a pleasant and inviting environment for swimmers to enjoy.

How do you use Pool Flocculant?

  • Read directions
  • Turn the filter to the ‘Recirculate’-for 2 hrs.
  • Adjust pH-7.4- 7..6.
  • Determine the amount using the volume of your pool to gals.
  • Dilute in a 5 gal. bucket-pour around pool edges
  • T/Off pump & leave sit for 8 hrs.
  • After 8 hrs., turn the filter to ‘waste’, & vacuum the pool
  • Refill pool-Balance .……………………………………………………………..Read more

JimGalloway Author/Editor


River Pools- Beginner Guide to Flocculants


How do I use pool flocculant?

The specific usage instructions can vary depending on the product, but generally, you’ll add the flocculant to the pool water according to the manufacturer’s guidelines, often near the pool skimmer with the pump running. After allowing the flocculant to circulate for a specified period, you’ll typically turn off the pump to allow the particles to settle before vacuuming or backwashing the pool.

Is pool flocculant safe to use?

When used according to the manufacturer’s instructions, pool flocculant is generally safe for use. However, it’s essential to follow all safety precautions, including wearing appropriate protective gear and keeping the chemical out of reach of children and pets.

Can I use pool flocculant with other chemicals?

Yes, pool flocculants can typically be used in conjunction with other pool chemicals. However, it’s essential to ensure that the chemical balance of the pool water remains within recommended levels and to avoid mixing flocculant with certain chemicals, as this can lead to undesirable reactions.

How long does it take for the pool flocculant to work?

The time it takes for a pool flocculant to work can vary depending on factors such as water temperature, circulation, and the severity of the cloudiness. In general, you may start to see results within a few hours to overnight, but complete clarification may take up to 24-48 hours.

What should I do after using the pool flocculant?

After using pool flocculant, it’s important to follow up with proper filtration or vacuuming to remove the clumped particles from the water effectively. You may also need to backwash the filter or clean the pool pump to ensure optimal performance.

Can I swim in the pool after using a flocculant?

It’s generally recommended to avoid swimming in the pool while the flocculant is actively working, as the water may be cloudy or contain concentrated chemicals. Once the flocculant has settled and been removed through filtration or vacuuming, and the water has been properly balanced, it should be safe to swim.

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