Blog

Jun
25
Alternative sanitizers offer options to chlorine

Ask not what your chlorine can do for you but what you can do for your chlorine.

There is a silver lining to the nationwide trichlor shortage; it is forcing pool and spa service techs to consider the alternatives.

For many service technicians, chlorine tabs are the go-to when it comes to pool care. Using trichlor tabs is a simple and easy way to maintain a chlorine residual. Furthermore, using tabs doesn’t require extensive storage space and it weighs less than liquid, causing less wear and tear on the truck.

But we have to use what we can, so how do we get more out of the chlorine options that remain available?

Now is a great time to test cyanuric acid and get it down to reasonable levels. While it is necessary to have cyanuric acid in the water to protect it from being burned away by sunlight, too much cyanuric acid will require more chlorine to perform the same job. The rule of thumb is that the amount of chlorine needed to prevent an algae bloom is 7.5% of the cyanuric acid. So, with less cyanuric acid, less chlorine will be needed. Cyanuric acid levels between 30 to 50 ppm are recommended so reasonable chlorine concentrations can be maintained.

Next, consider phosphate removal. Chlorine demand tends to be higher in swimming pools with high phosphate levels. It is not that chlorine and phosphates interact with one another. Rather, it is because high phosphates help fuel algae growth. Phosphates are known algae nutrients so lowering phosphates to below about 500 ppb can reduce the workload that chlorine must perform.

Simply removing phosphates does not itself kill algae. Instead, it is a preventative measure to reduce the growth and reproduction rate of algae in the first place.

The IPSSA Basic Training manual says “Algae can double in population in about 3 to 8 hours. To prevent uncontrolled growth, the kill rate [of chlorine] must exceed the growth rate for bacteria or algae.”


More phosphates leads to a higher reproduction rate so it’s a race between the reproduction of algae and killing it with chlorine. Phosphate removal puts a handicap on algae.

Pool operators can also consider borate use to reduce algae growth. Borates are not algicides, they are algestats, and there are published studies that have demonstrated this. Users of borates have significantly reduced algae growth, even in pools with high phosphate levels.

Another step is to consider weekly enzyme use. Depending on the formulation used, many enzyme users have observed noticeably better water quality when chlorine is supplemented with enzymes. Similar to phosphate removal, enzymes don’t kill anything in pool water. Rather, they reduce organic contaminants such as lotions and some types of bather waste that also put a strain on chlorine.

If supplies are available, consider getting a salt water chlorine generator so that the pool can produce its own chlorine. Although there are plenty of service professionals that don’t like chlorine generators for a wide variety of reasons, with the ongoing chlorine crisis, many of these are willing to recommend them now, if they can get their hands on them.

Finally, if customers can afford it, service techs can also recommend UV, ozone, or better yet or UV-Ozone AOP systems, which does an excellent job of supplementing chlorine. Combining UV with Ozone in an AOP system creates synergistic sanitation that maximizes water clarity, disinfection and chloramine removal.

By Marcelle Dibrell