Does Pool Flocculant Reduce Hardness

Using a Flocculant treatment in your pool has benefits besides using it to turn a green algae pool once it loses control maintaining proper levels the calcium hardness and other minerals will go a long way to providing a balanced and healthy swimming pool. Does pool flocculant reduce hardness?

Yes, a flocculant treatment will help settle out free-floating minerals such as calcium & remove them by wasting them from the system and replacing the H2O lost from the pool. Flocculants can only cause minerals out-of-solution to stick together so dissolve calcium can’t be removed from the pool H2O

Maintaining proper calcium hardness in your pool is critical to the quality of your overall pool health. High calcium hardness in your water can cause corrosion of the pool plumbing and can even cause scale to build up on the surfaces of the pool making them rough.

Does Pool Flocculant Reduce Hardness


Yes, a flocculant treatment will settle out minerals such as calcium and remove them by vacuuming them from the floor of the pool, bypassing your sand filter and wasting from the system. The water that was wasted should be replaced. Fresh water should cut the amount of calcium carbonate and other heavy metals building up in the pool water. This is true unless the supply water contains a higher amount of calcium hardness. Test the faucet or hose water coming into the house for levels of calcium hardness.

The hardness of water is determined by the milligrams of calcium carbonate per liter and is reported in parts per million (ppm). In general

  • water with less than 60 ppm can be considered soft
  • water with 60-120 ppm is moderately hard
  • water with greater than 120 ppm hard.

The ideal calcium hardness level is somewhere between 150 to 400 ppm in a pool. Once it gets too high, the water becomes hard, which can consequently lead to cloudiness and to calcium buildup not just in the pool water, but in the pool plumbing as well.

The water in your pool appears cloudy and you notice sediment buildup on the bottom, and adding clarifiers and shock doesn’t solve the issue, you likely have hard water. Test the water with a reliable  Pool Testing Kit to determine the calcium level.



Can I Use Clarifier After Flocculant?

Clarifiers are used after Flocculant

Removing light floc left over from quick-settling heavy floc
Floc knocked into suspension vacuuming
High TDS/Salt in H2O prevents flocculation.
Using too much flocculant
Low pH start ………………………………………………………………………….. Read more


It should read between 155 and 400 parts per million (ppm); aim for about 275 ppm for the most balanced water.  To achieve the ideal calcium level, pool professionals first balance the water’s pH, then the alkalinity, and finally the calcium.

  1. Use a flocculant to rid the pool of free-floating calcium carbonate.
  2. Vacuum the walls and floors of the pool, so the excess calcium carbonate particles are pulled into the pool filter.
  3. Backwash or clean out your pump filter.
  4. Drain a portion of your pool water and refill it with fresh water.
  5. Test the pool water for calcium hardness.  With the excess calcium carbonate removed and fresh water added, you can notice a reduced calcium hardness level.

Using a flocculant before draining and replacing the water can help reduce calcium hardness in a swimming pool with a water hardness significantly higher than 400 ppm. Flocculant is an additive that removes free-floating calcium (undissolved calcium) from the pool water.

After adding the flocculant to the water and vacuuming the sides and bottom of the pool to remove the remaining calcium carbonate particles, backwash the filter. There are really only a few ways to lower your pool’s high calcium hardness level and that is to:

  • Partially or completely drain your hard pool water and replace it with fresh water. The first option to make your pool water softer is to drain some water and add some new, fresh water. Start by turning off your pool. Then drain just a few inches of water from your pool with a pump. If you have access to a fresh (not hard) water source, use that to replace the drained water
  • Use a Flocculant treatment on your pool water
  • Muriatic Acid-won’t actually reduce the water’s calcium hardness, but it will raise the saturation level, which can help bring the water back into balance.


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 .……………………………………. Read more


JimGalloway Author/Editor


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