Cyanuric Acid and Chlorine Lock in Swimming Pools
Cyanuric acid is used to protect unstabilised chlorine in water. Without a stabiliser, chlorine is broken down by the sun’s UV rays, rendering it ineffective. The ideal Cyanuric level for a swimming pool is typically between 30 and 50 parts per million (ppm).
However, over time, cyanuric acid levels will build up in the pool, and as they exceed 50-70 parts per million (ppm) it will lead to the phenomenon known as “Chlorine Lock”.

How does Cyanuric Acid get into the swimming pool water?
If you are using either liquid chlorine or calcium hypochlorite then these two products are not stabilised. To make these more efficient in the water and not burned out by the sun’s UV rays, then you would add cyanuric acid in powder form, commonly known as ‘stabiliser’.
Other chlorine based products such as stabilised chlorine granules, multifunctional chlorine granules, chlorine tablets (20gm or 200gm) and multifunctional tablets all have the cyanuric acid built in.

What is Chlorine Lock?
Chlorine in swimming pool environments is measured in three ways:

• Total Chlorine- The total amount of chlorine present in the pool.
• Free Chlorine- The amount of chlorine in your pool that is actively sanitising your pool.
• Combined Chlorine- The amount of “used” chlorine that is no longer sanitising.

Chlorine Lock is when your chlorine is rendered useless no matter how much chlorine you add. What you will find is that no matter how much chlorine you add, the levels of free chlorine will not go up.

One of the main causes of this is that the cyanuric acid levels are too high.

What is the “traditional” method for addressing Chlorine Lock?
Chlorine Lock is not a problem that will go away by itself, nor is it particularly easy to solve, but there is a proven cure.is not a problem that goes away by itself nor is it particularly easy to solve, however there is a proven cure.

Dilution refers to the act of partially draining a pool (by about a quarter) and refilling it with fresh water. This is necessary because Cyanuric acid does not dissipate over time so therefore needs to be actively removed.

If, after testing, the free chlorine level has not returned to an appropriate level, or if the free chlorine does not increase when added, this process must be repeated.

Not only is this a very time-consuming process, but it also uses a lot of chemicals as the water needs to be re-balanced. Fresh water is also expensive and must be heated to the right temperature. Then there is the fact that we must dump water in the first place, which is a precious natural resource.

What is Lo-Chlor’s solution to Chlorine Lock?
Our approach to Chlorine Lock is simple and incorporates one of our core principles as a brand: “Prevention is better than cure”. If we can prevent problems from occurring in the first place, it is far better than having to deal with them effectively.

Since chlorine lock occurs over time as more and more stabilised chlorine is added to the pool, using less chlorine is a logical way to prevent it.
Therefore, we need to ensure that we maximise the life of our chlorine by reducing the demand for it in the water.

Reducing the demand for chlorine means using other methods to deal with the problems that your chlorine must deal with, so that it can concentrate on the jobs that only it can do, such as destroying any harmful bacteria.

Reducing Phosphates
Lo-Chlor Starver X is a concentrated phosphate remover. Phosphate is one of the main sources of algae growth and by removing it we can reduce the risk of algal blooms occurring. Algae control is one of the key functions of chlorine in water, so if we can prevent algae from forming in the first place, we eliminate the need to use chlorine to control algae. To quantify this saving, we have conducted trials in Cyprus which show savings of up to 60% over the course of a year.

Chloramines are another major way chlorine is used unnecessarily in our pools. These are formed when chlorine combines with oils, fats and other waste products in the water and are the cause of the infamous ‘chlorine smell’. Lo-Chlor Ultra Pool Clarifier+ is not only a quick and effective way of clarifying water, but also able to remove these fats and oils before they can react with chlorine and use it up. Trials show that this can also result in significant savings over a year.

Therefore, by running our pool on a treatment system that incorporates both Starver X and Ultra Pool Clarifier+, we can maximise these chlorine savings, meaning that we add less cyanuric acid to the water and therefore prevent the risk of chlorine lock occurring, saving time, money and resources.