Chlorination without using Cyanuric Acid

Written By Timothy Te

02nd February 2021

If you’re reading this right now, then you’re probably having problems with high levels of cyanuric acid rendering your pool chlorine ineffective, that or you’re just naturally curious if it’s possible to chlorinate your pool without using cyanuric acid for protection.

The simple answer to that is, well, there is no simple answer to that. If you have an indoor pool or a spa that isn’t exposed to sunlight, then yes, you can get away with not using any cyanuric acid or stabiliser. But if you have the pool in a location exposed to sunlight then you have to use cyanuric acid to protect your chlorine so that it can survive under the sun long enough to do its job. No matter what anyone says, you will need cyanuric acid for your pool, unless of course you want to stand there poolside with a shovel dumping chlorine into your pool every hour and you have unlimited funds to burn on purchasing chlorine.

Why is it needed? If you love science, you can check out this paper here available on the QCAA and read up on the specific effects of sunlight on swimming pool chlorine in an unstabilised state. But if you’re not the sciencey type, then here’s the TLDR (Too long didn’t read) version: Without cyanuric acid, you’ll be losing half of your free chlorine under 20 minutes! (17 if you want to be precise).

Sources of Cyanuric Acid

Obviously, we have pure cyanuric acid or stabiliser as your main source of cyanuric acid for your pool. But there are other sources as well that add cyanuric acid to your pool like chlorine pucks. These pucks, or Trichlor are, believe it or not, more than 54% cyanuric acid by weight! We’ve had issues before where pool owners were telling us that the chlorination of their pool was getting worse by the day and they were using more chlorine but the more chlorine they used, the worse it became. When we asked what chlorine they were using, they said they were using chlorine pucks or trichlor tablets, and they were inadvertently raising the cyanuric acid levels of their pool making their chlorine ineffective!

Our suggestion to this is to basically get your cyanuric acid levels to 10ppm - 30ppm level and then switch your chlorine to liquid or unstabilised chlorine. The reason for this is that cyanuric acid is a very hardy pool chemical. It doesn’t evaporate and as long as the water stays in the pool then your cyanuric acid levels will be pretty stable.

When do cyanuric acid levels go down?

Like we said previously, cyanuric acid is very hardy and it won’t go down on its own, unlike other chemical levels that are affected by UV or will swing due to other chemical levels, cyanuric acid levels will only go down if drained from the pool. While out of mind, the main causes of cyanuric acid levels dropping (only slightly) will be when you backwash your sand filter, vacuum to waste, or if you’re draining your pool after a pretty bad rainstorm.

Note: Contrary to popular belief, adding water to your pool to refill water loss due to evaporation will NOT lower your cyanuric acid levels.

Update: If you have a problem with overly high cyanuric acid levels, check out our product spotlight on the Bio-Active Cyanuric Acid Reducer! This compound eliminates the need to partially drain or dilute your pool to lower your stabiliser levels!

I have the proper cyanuric acid levels, what now?

Switch out your stabilised chlorine or chlorine pucks to unstabilised chlorine to keep your cyanuric acid from rising further! Monitor your pool’s cyanuric acid levels with some test strips, an once you see them straying to the low side, test them with a good reagent test kit to see exactly how much you need to add to get them to their proper levels. So yeah, confusing right? It's a juggling act of using unstabilised chlorine, stabilised chlorine, chlorine pucks, and cyanuric acid!

That sounds too complicated, is there a better way?

Yes, when it comes to pool maintenance, there’s always a better way! Here at Mr Pool Man, we’re heavy proponents of making pool maintenance much easier so that you’ll have more time enjoying your pool! Remember how we said earlier that you can stand poolside shoveling chlorine into your pool? You don’t have to do that because that’s what Salt Water Chlorinators are for! Taking salt from your pool, salt water chlorinators constantly produce chlorine for your pool so that you won’t have to do the dosing yourself. It may take some balancing at first to hit the correct cyanuric acid levels for your pool, but once you’re at the proper levels, you no longer have to switch between stabilised and unstabilised chlorine or play around with unstabilised chlorine + cyanuric acid to get the balancing act together.

Water TechniX Atomic WTA35 Salt & Mineral Chlorinator - 35g-Chlorinators-Mr Pool Man

Sold out

Doesn’t that sound great? Only adding cyanuric acid or stabiliser if you drain your pool or if you do backwashing? No more worrying about constantly checking cyanuric acid levels when you chlorinate? While the initial outlay for a salt water chlorinator will seem high at first, the time and effort saved in worrying about cyanuric acid levels and chlorination more than makes up for it!

Want to eliminate worrying about cyanuric acid forever? There are some options out there, you can see our take on Naked Pool Systems here.

Need more information on Cyanuric acid? Is it friend or foe? Read our comprehensive write-up here.

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

We Need This
We Need This
We Need This
Thank you!
Written By

Timothy Te

Pool Guru at Mr Pool Man

Sign Up for Offers, New Products, DIY Tips and More