How to Break Chlorine Lock in Swimming Pools

Chlorine lock is a common problem for pool owners. It means that the chlorine in the pool is useless and the water is not sanitized properly. And in this article, we check on how to break chlorine lock in swimming pools.

How does chlorine lock occur?

So how does chlorine lock occur?

Chlorine lock can happen when there is too much cyanuric acid in the pool water.

  • Unbalanced pH

An unbalanced pH can also a cause of chlorine lock. The fastest way to check if there is a chlorine lock is to test the pool water.

What is chlorine lock?

The occurrence of chlorine lock happens when a pool is free chlorine is sometimes overwhelmed by its cyanuric acid. When chlorine drops it also drops the ability to kill bacteria. And because of this, it will allow algae and bacteria to take over your pool.

How to fix or correct chlorine lock?

When you found out that you have chlorine lock in your pool the first thing you want is to fix it, right? So, here are some tips in fixing your pool chlorine.

  • Test the pool water

Test the pool and water and record the pH, free chlorine, total chlorine, CYA and calcium hardness. You need to record everything to make it easier for you to fix it.

  • Partially drain the pool

It will give your pool sort of a refresher and allow you to start with some cleaner water.

  • Non-chlorine shock

Another way to break chlorine lock is to shock the pool with a non-chlorine shock. The non-chlorine shock will oxidize the chlorine in the swimming pool.

Non-chlorine shock oxidizes the water, restoring the balance and making it cleaner.

  • Chlorine shock

To break chlorine lock with shock, breakpoint chlorination is being done.

This is where large amounts of chlorine are being added to break up the chemical bond of the chloramines. And chlorine shock is the best product to use for this method.


Having a chlorine lock sometimes does take a little work to break. But it is very essential to keep your pool clean and safe for all. So make sure to check it on a regular basis to prevent chlorine lock.

And for all your pool needs call My Pool Guy for your pool guy!