How to Lower Stabilizer in Swimming Pool Water If Level Is Too High
Dilution Is the Solution
First thing's first. You cannot add chemicals to lower the stabilizer level. Cyanauric acid (a stabilizer) can be added, but in order to lower it, the pool needs to be diluted with fresh water. There is no chemical on the market that you can add to your pool water to lower the stabilizer.
If you just need help with cleaning a green pool, learn how to properly shock your pool.
What Happens When You Have Too Much Stabilizer?
If the stabilizer level is too high in a pool it, will lock the chlorine molecules, rendering them ineffective as a sanitizer. This usually happens as a result of using chlorine tablets that contain cyanauric acid. Pools that sanitize the water using salt systems or other methods other than tablets usually don't have this problem.
Although you will get a chlorine reading—sometimes a high chlorine reading—your pool may still have algae or other problems. This is because the chlorine molecules are locked up by the high cyanuaric acid level.
What's the Ideal Level for Pool Chlorine Stabilizer?
You should aim for a stabilizer level between 30 and 50ppm. Test the stabilizer or have your water tested and see what the stabilizer level is. Some pool stores list it as either stabilizer or cyanauric acid level.
I service some commercial pools, and the county health inspectors like it below 100ppm, which makes sense because the chlorine is usually very controllable and effective below this level. However, for most homeowners, shoot for 30–50ppm.
How to Dilute Your Pool Water to Lower the Stabilizer Level
Depending on your stabilizer level, and of course the size of your pool, unfortunately, you are going to have to drain a significant amount of water from the pool. Some customers I have don't like this because of the cost of replacing the water. However, if you don't do this, you will have recurring problems. If you have a cartridge filter, you may want to learn how to clean a cartridge filter. Many problems can be caused by a bad filter.
Draining the Water:
Most pool pumps have more than one valve coming to the intake side of the pump. (Skimmer/Main drain) sometimes a third cleaner line. In any case, you need to close the skimmer line and open the drain valve on the return side. (If you don't have a drain valve, have one installed! You'll need it anyway.)
Drain about two feet of water from the pool. Yes, 18-24 inches below the bottom of the tile line.) This is why the skimmer line needs to be closed. Reset the valves and add water from the hose. This can take several hours depending on the size of the pool and water pressure from your hose. Let the pool filter on normal cycle and have the stabilizer re-tested. There should be a significant decrease in stabilizer.
You may also be intersted in:
- How to get rid of black algae
- Advanced pool water chemistry
resolving issues with pool water when chlorine, pH, and alkalinity are in balance. Why is my pool still getting algae?
- How to turn your swimming pool from green to clean
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Is there any other way to lower the stabilizer in a swimming pool?
No. The water needs to be diluted with fresh water. I know that a product came out recently that supposedly lowers stabilizer, but I can say with confidence after trying it, that it doesn't work and it's costly. Calcium hardness is the same way. If it's too high, the water needs to be diluted.Helpful 28
Why does my chlorine test high? It's orange instead of yellow, but I haven't added chlorine for a week.
The test reagents are most likely bad. They have a shelf life and can create false readings if they haven't been replaced in a while.Helpful 25
How do you make the stabilizer level in the pool higher?
Add Stabilizer (cyanauric acid)Helpful 10
Do you add the stabilizer chemical to the pool or the water return?
You will add the stabilizer directly into the skimmer. Stabilizer does not dissolve quickly, so it's not a good idea to put it directly into the pool; however, it will gradually dissolve when added through the skimmer.Helpful 5
Why would pool water turn clothes and skin green/blue?
This is a water chemistry issue. I recommend having a full parameter chemical test done professionally, including a metals test (Iron and copper).Helpful 4