Cloudy Water and Algae in a Baquacil Pool

Dr pool holding a bottle of splashes sanitizerHello again, I’m Dr. Pool, resident chemist at In The Swim. Today’s lecture is about Cloudy Water and Algae in a pool treated with Biguanides, an alternative to chlorine.

Polyhexamethylene Biguanide, (PHMB), is biocidal and fungicidal and is used as a disinfectant, as is chlorine.

PHMB’s are sold under trade names such as Baquacil, Revacil or Soft Swim. We offer an improved formulation of Polyaminopropyl Biguanides, known as Aqua Silk.

Using a biguanide has certain benefits over chlorine. Splashes is unaffected by sunlight, pH and water temperature. It also transforms the pool water contaminants they attack into more easily filterable clumps, by creating larger insoluble complexes of the algae and bacteria they consume.

Just like chlorine treated pools, there can be issues with cloudy water or algae. With biguanides, these conditions are treated similarly, but with different chemicals. As with any poor water condition, filter performance plays a large role in restoring and maintaining clean and clear pool water.

Cloudy or Hazy Pool Water in a Biguanide Treated Pool

1. Check your water balance. Aqua Silk and Baquacil are not overly pH dependent, but excessively low or high calcium hardness or total alkalinity levels can cause carbonates and minerals to precipitate – making the water hazy or cloudy.
2. Check your sanitizer levels, to maintain the optimum level.
3. Shock with your oxidizer to remove any bacteria in the water, and help improve filtration. If cloudiness persists, use Cloud-Out shock.
4. Run the filter pump 24 hrs per day while correcting cloudy water. Backwash or clean the filter when pressure rises 8-10 lbs.

Algae in a Biguanide Treated Pool

Algae treatment for a Splashes pool, or one treated with Baquacil is done in nearly the same way as the treatment for cloudy water – and again, proper and effective filtration is a very important part of the equation.

1. Check your water balance. Algae prefers high pH and low alkalinity levels.
2. Check your biguanide sanitizer levels, to maintain the optimum level.
3. Shock with your biguanide oxidizer to a level that kills the algae. Use Cloud Out pool shock if your algae is white or pink colored.
4. Run the filter pump 24 hrs per day while treating for algae. Backwash or clean the filter when pressure rises 8-10 lbs.
5. Follow up with a regular treatment of Algaecide 50, to keep algae under control.

3 Tips for Filtering a Splashes or Baquacil Pool

Clean Your Filter

tips-for-baquacil-poolsClean your filter every 3 months of operation, using a brand-approved granular pool filter cleaner. If this is not done, these insoluble complexes mentioned above will begin to reduce your filter’s effectiveness, by attaching themselves to your filter media.

Use our Granular Filter Cleaner with Baquacil or Splashes and others every 3 months, to help the filter from becoming clogged with a gummy substance created as the biguanides remove the contaminants from your pool water.

When cleaning filter cartridges and DE filter grids, use a high pressure hose (but not a pressure washer) to rinse them thoroughly before and after soaking in the Splashes pool filter cleaner. Allow to dry before reinserting into the filter tank.

Is your Filter Bypassing Water?

tips-when-using-baquacil-revacil-soft-swim-splashes-biguanidesYour filter should be building pressure on the gauge. If the pressure doesn’t rise or rises very slowly, inspect for the possibility of your filter allowing some portion of water to return to the pool unfiltered.

Multiport valves and Push Pull valves on DE and Sand filters can also bypass the pool filter if the filter valve, also called the backwash valve, has internal problems. Water will slip past if there are damaged gaskets or missing o-rings, or if there are broken parts on the inside of a multiport or slide valve.

A filter or valve that is bypassing water will usually indicate this by bypassing very light materials. On some systems, a small scoop of DE powder or pool conditioner, added to the skimmer will return into the pool visibly and quickly, if your filter or valve is bypassing any measurable amount of water.

Inspect your filter media for any way in which water may be bypassing. Sand filters can develop channels of water flow, or the sand bed can calcify in some parts. DE filters can bypass the grids through a crack in the manifold or a loose grid assembly. Cartridge filters can send water around the cartridge element and not through the pleats, if internal parts are missing or the cartridge is incorrect, damaged, or misaligned.

Replace Your Pool Filter Media

tips-for-pools-that-use-biguanidesEventually, the practice of cleaning your pool filter with the granular filter cleaner will be less effective. If your filter is a bit undersized for the job, this can hasten the need for replacement of the pool filter media (sand, cartridge or DE grids).

Filter sand and filter cartridges used in a biguanide environment should be replaced every 2-4 years, while DE filter grids which are cleaned regularly can last twice that long.

The length of the time between filter cleanings, known as the “filter cycle”, can be a good indicator of when it’s time to change the filter media. If you are cleaning the filter twice as often as you once did, you can assume that it has reached it’s half-life of filtering performance.

4 Tips for using Splashes and Baquacil Pool Chemicals

  1. Maintain proper levels of Aqua Silk Sanitizer, and Aqua Silk Oxidizer.
  2. Maintain proper water balance – pH, Alkalinity and Calcium Hardness.
  3. Maintain proper filtration, and use a filter cleaner every 3 months.
  4. Replace your filter sand or filter cartridges every 2-3 years.

If you have questions about any of this, or if you have other issues besides cloudy water or algae in pool using Aqua Silk pool chemicals, or Baquacil, let me know by leaving a comment below, and I will answer personally.


Dr. Pool


Cloudy Water and Algae in a Baquacil Pool — 2 Comments

  1. We use Baquacil – it not cloudy – just not sparkling!what do you suggest – we are using floculant
    The ph level is 6.4 The pool company in our area gave me PH up to put in but its not for Baquacil treated pools – I haven’t used it yet – is that safe?

    • Hi Susan, you can use any brand of pH, alkalinity or calcium increaser, without a reaction to Baquacil. You can also use any clarifier, flocculent or any algaecide that may be needed. Just don’t use any chlorine products, or any type of powdered shock (chlorine or non-chlorine). If your filter is on the small side, you can add the Slime Bag product on the return wall fitting, to act as a secondary filter. Baquacil tends to gum up pool filters, so you may want to use a filter cleaner product twice per year, and change the media (sand or cartridges), every other year.

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