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Using a Flocculant Clarifier to Clear a Cloudy Pool

Rob is a pool-service industry professional with over 20 years of experience.

Using a flocculant clarifier to clear your cloudy pool is cheap and efficient!

Using a flocculant clarifier to clear your cloudy pool is cheap and efficient!

If you've tried everything and are still struggling with a cloudy or green pool, there is something that might be suitable to try. A type of clarifier known as a flocculant, commonly called "drop n' vac" or "dropout," is a solution that, when added to water, can clean your pool.

Steps to Cleaning Your Pool With a Flocculant

  1. Drop the clarifier into your pool.
  2. Vacuum out the "dust."
  3. Understand how your waste valve works (also, what to do if you don't have a waste valve).

Step 1: Drop the Clarifier Into Your Pool.

After dropping in the flocculant, cloudy particles bind together, and the larger particles sink to the bottom of your pool. This will result in the water being clear, but now the bottom of your pool is dirty.

What to Remember After Dropping in Your Flocculant

  • Remember, despite the clear water, the floor of your pool is now covered with sunken algae.
  • This sunken algae is very light and is often referred to as "dust." Don't try to brush it away. This would defeat the purpose of having added the flocculant to begin with.
  • This waste will need to be vacuumed from the pool through the waste valve.
Flocculants clump organic matter. The heavier clumps sink to the bottom, cleaning the water.

Flocculants clump organic matter. The heavier clumps sink to the bottom, cleaning the water.

Step 2: Vacuum Out the Waste

After the flocculant has been added, let the pool water sit still for 24 hours with the pump off. This will allow the debris and algae to sink to the bottom.

This waste will need to be vacuumed through the waste valve. Waste vacuuming is the simple process of pumping the vacuumed water out to the yard, street, etc. Some filter systems are set up for this. These systems contain a valve that drains water out of the pool.

What to Remember When Vacuuming Your Pool

  • Try to avoid any water being vacuumed back into the pool.
  • The vacuum process will be slow, since the particles on the bottom are very light and will stir up easily.
  • The water level will drop some, so you will need to add more water to the pool when you are finished.

Step 3: Understand Your Valve or Filter

If you are using a DE filter, most of them will have a multi-port valve with a "waste" position on them. Some cartridge filter systems I've seen are plumbed for filtration and recirculation, but with no way to drain or vacuum the dust out to waste.

What to Do If You Don't Have a Waste Valve

  • One solution would be to open the filter, take out the cartridge and vacuum with the water overflowing out of the cartridge and away from the pool. Unfortunately, this method will flood the area around the pump, but at least some of it is going out to waste.
  • If you don't have a return line shut-off, some will still get back into the pool.
  • I highly recommend having a waste line plumbed in. You'll only need to install a valve or two. You'll need some glue and some fittings. It's not difficult or expensive to install.
Vacuuming to waste with no waste valve. Notice I've taken the filter out while vacuuming the pool. Click to view larger image.

Vacuuming to waste with no waste valve. Notice I've taken the filter out while vacuuming the pool. Click to view larger image.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.