By The Zagosa Team. Published .
Reviewed or updated .
We get asked a lot at Zagosa Spa & Pool what the difference is between these two forms of chlorine and which one to use. For years bromine has been a popular choice for on-site sanitation because it is non-chlorine, which suits hot tubs and spas since it does not dry the skin the way some chlorinated pools can.
But there is more to the choice than that. Let us set out everything you need to know so you can decide for yourself. Here we go.
Say you have weighed up bromine versus chlorine and picked chlorine for your hot tub, spa or pool. The next question is which chlorine suits you best: stabilised chlorine granules or multifunctional chlorine tablets?
Your multifunctional chlorine tablets say they contain un-stabilised chlorine. So what is that?
Un-stabilised chlorine is chlorine without cyanuric acid added. Cyanuric acid stabilises chlorine, which in effect makes it last much longer in your spa or hot tub. Plenty of multifunctional tablets use the un-stabilised form, so it is worth reading on to see how that affects the water management of your hot tub (bearing in mind they have many other benefits too).
Un-stabilised chlorine dissipates more quickly, so you will need to add more to keep your water sanitised. That is especially true in summer, when the sun's UV rays burn the chlorine off faster.
That said, if your pool, hot tub or spa is undercover, un-stabilised chlorine could be the better fit, since UV will not touch it. Just remember that without the stabiliser (cyanuric acid) it will not stay in the water long. Daily testing is essential, topping up chlorine when needed to hold the optimal 3ppm.
What is stabilised chlorine?
You have guessed it. Stabilised chlorine does contain cyanuric acid, which keeps the chlorine in your water longer and more efficiently, so you do not have to add as much, or as often, as with un-stabilised chlorine.
Stabilised chlorine usually comes as granules, which dissolve much faster than multifunctional un-stabilised tablets, giving you a quicker response when your readings change. That is another reason granules are excellent for shocking your hot tub water.
One word of warning, though: if your cyanuric acid (the stabiliser) climbs too high, it starts to work against the chlorine itself. If that happens, we suggest a partial drain-down to dilute the concentration and rebalance the water.
Should I use stabilised or un-stabilised chlorine?
We are not ones to sit on the fence at Zagosa Spa & Pool, so we like to give a clear recommendation, but honestly there is no right or wrong answer here. It comes down to understanding what hot tub, spa or pool you have, where it sits, how each form is used, and your own preferences.
Many of our customers do not choose one over the other at all. To get the water just right, they use a mix of multifunctional chlorine tablets and chlorine granules, and we rather like that approach.
Hassle-free multifunctional tablets in a dispenser are great for day-to-day chlorine maintenance. Pair them with stabilised chlorine granules for shock-dosing and quick adjustments and you get spot-on water chemistry.
To find what works best, try both alongside your daily testing and you will soon settle on your ideal combination. If you want to talk chlorine with one of our water management experts, call 02921 280422 or WhatsApp 07540 184405.