Polyhexamethylene Biguanide (PHMB) is biocidal and fungicidal and is used as a disinfectant, as is chlorine.
PHMBs 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. Aqua Silk 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 hours per day while correcting cloudy water. Backwash or clean the filter when pressure rises 8-10 pounds.
Algae in a Biguanide Treated Pool
Algae treatment for an Aqua Silk 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 hours 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 an Aqua Silk or Baquacil Pool
Clean Your Filter
Clean your filter every three 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 Aqua Silk every three 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 Aqua Silk pool filter cleaner. Allow to dry before reinserting into the filter tank.
Is Your Filter Bypassing Water?
Your 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
Eventually, 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 two to four years, while DE filter grids that 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 its half-life of filtering performance.
4 Tips for Using Aqua Silk and Baquacil Pool Chemicals
- Maintain proper levels of Aqua Silk Sanitizer, and Aqua Silk Oxidizer.
- Maintain proper water balance: pH, alkalinity and calcium hardness.
- Maintain proper filtration, and use a filter cleaner every 3 months.
- 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.
We use Baquacil and we have a cloudy pool. We can’t see the bottom. What do we need to do you get our clear pool back?
Visit your baquacil dealer, they may have a solution. I would suggest that the filter media be changed if not done recently.
Hi I’m a newbie to the pool game so bare with me…. I have a 21’ round above ground pool that is full of what I guess is algae. The problem is I can’t get that out of the pool. I use a baquacil and since opening I have put 2 gallons of oxide plus 1 container of algae code and then a bottle of sanitizer. It has done nothing! My pool place hasn’t been much help. We live in Michigan so
Time is
Of the essence. Thanks in advance
Hi Chad, I would look at the filter, you most likely need to replace the media (sand or cartridge), which gets gunked up with Baquacil, in just 1-2 seasons. Secondly, run the filter 24/7, and third, keep the baquacil levels high, and fourth be sure the water is balanced (ph, alk, calcium) perfectly.
Is there a special type of filter system I should use for aqua slik use. we are about to repaint our pool as algae is thriving in it. A friend mentioned that the filter system we have that came with the house may not be correct type of filter.
Hi Brian, the best filter type for biguanides is a sand filter, a large one, a 30″ tank is best for pools 20-30,000 gallons
Using aqua silk. What do I need to look for when using a different algecide?
Also is there another shock to use other than the oxidizer?
Hi, for algaecide, polymers can be used, look for one with 30 or 60 in the name, like Poly 60 or our own Algaecide 60 Plus. Do not use those with 10 or 50 in the name, which are quats. For the shock, use only the Peroxide shock offered by Aquasilk, or your brand of biguanide. Do not ever use any chlorine products, and using non-chlorine shock will also cause problems.
We have a baquacil pool and it is cloudy we have tried floc and pretty much everything but still cloudy my granddaughters b’day party is this Saturday and we need it cleared up please help
Hi Laurie, have you tried new filter media? Baquacil and other biguanides clog up filter sand, cartridges and DE grids, and require frequent use of Filter Cleaners, and frequent filter media replacement. I would do that if you have not done so already. Secondly, have you tried a Clarifier? Another thought is the Slime Bag, a secondary filter that fits on your return line.
Can baking soda be used in a baquacil pool?
Hi, Patricia, yes it can for raising total alkalinity (not to be confused with baking powder!) Sodium Bicarbonate or Bicarbonate of Soda – aka baking soda, yes – is the same as our Alkalinity Increaser
Use baquacil have no pressure on return. Just put in new sand works good for couple of days then looses pressure again. Any thoughts on what the problem might be?
Hi Steve, if your pressure gauge goes very high, when flow goes low, it could be the sand gunked-up. Double check that the proper type and amount of sand was used. You can inspect it by digging your hands into the top few inches. Could also be a pump that is not properly sized for the filter, too big or too small. If the pressure is lower than normal, check for an air leak in front of the pump, or a pump problem.
Pool became cloudy end of last summer after heavy rain. adding chock and algaecide didn’t work and when closed pool for winter water still cloudy. opened pool recently water still cloudy. have added shock and algaecide, have DE filter. soaked and cleaned fingers (blades), added a clarifier. ran pool for several days and no change. selling house soon. Would like to have a clear pool. Suggestions please. Thanks
Hi, for the fastest clean-up, drain the pool and refill it. For a vinyl or fiberglass pool, drain until 6″ from the shallow end floor and refill. Balance the chemistry first – ph, alkalinity, calcium hardness and stabilizer – all should be in range for clear water. Then shock the pool heavily, and two days later add a clarifier. Finally, run the filter 24/7 until water clears. Shutting off the filter each day can cancel any gains made earlier in the day.
We use Aqua silk pool system. Today we tested and our Alkalinity is WAY to high , caused burning eyes in our children 🙁
How do I lower the alkalinity?? Everything else seems to be fine, thank u…
Hi KP, alkalinity is lowered by adding a pH reducer (acid), which will also lower the pH. If very high, you may need to raise pH once or twice, during a process of several treatments – lower the alk, raise the ph, lower the alk, raise the ph… and so on, until your desired levels for both are reached.
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.