By The Zagosa Team. Published .
Reviewed or updated .
Spas and hot tubs rely on a range of chemicals. Getting your spa chemistry right matters for two reasons: the health of everyone who uses it and the working life of the spa itself. This post walks through the most popular spa chemicals and what they do for you and your spa.
Spa chemicals go by a few names, including spa sanitisers and hot tub or spa water treatments. Whatever you call them, they are central to keeping your spa healthy, hygienic and long-lived. The three main sanitising options are bromine, chlorine and biguanide.
The market has expanded fast in recent years, with more products on the shelf than ever, which leaves owners with a genuine choice to make. Bromine and chlorine are the two most common picks, because both knock out the microbes behind illnesses like Legionnaires' disease and E. coli.
Getting to Know Bromine
Bromine sanitises your pool, spa or hot tub by killing bacteria and algae. It has been a chlorine alternative for years, partly because it does not leave that strong chlorine smell hanging around after a soak.
It is also gentler on the eyes and skin than chlorine.
Brominated water is often called soft water, because bromine reduces or removes calcium and leaves the water feeling more delicate than other systems. Do not muddle a bromine system with a salt generator, which uses brine and salt to sanitise.
Bromine granules: the most common form for spas and hot tubs, though they turn up in pools too. Granules dissolve far quicker than tablets.
Bromine tablets: made by blending the brominating compound with a non-reactive carrier and pressing it into tablets. Bromine tablets dissolve slowly as water flows past, holding a steady level of sanitiser.
Bromine costs a little more to run than chlorine, but it lasts longer in your water.
Getting to Know Chlorine
Chlorine comes in several forms for spas and hot tubs. Granules and tablets are the most popular for value, though both need topping up now and then to hold the right level. You could fit a chlorinator to manage that automatically, or use liquid shock treatments that last a good deal longer than a single dose of granules or tablets.
- Longer-lasting treatment
- Cheaper per gallon or kg than liquid shock
- May need topping up more often due to evaporation, splash-out and so on
- Comes in different sizes, so easy to store
- Longer-lasting treatment
- More expensive per kg than granules
- May need topping up more often due to evaporation, splash-out and so on
- Comes in different sizes, so easy to store
Liquid shock treatments:
- Longer-lasting than granules and tablets
- Cheaper per gallon than chlorine tablets
- May need topping up more often due to evaporation, splash-out and so on
- Comes in different sizes, so easy to store
In short, granules and tablets are a solid way to manage your spa chemistry. If you want more convenience for less money, liquid shock treatments may suit you better.
Getting to Know Biguanide
The biguanide family is among the most popular chlorine stabilisers in use, valued for how it works to keep pool and spa water safe to swim in all year.
Professionals worldwide have relied on biguanides for years because they effectively prevent accidental biguanide precipitation.
They are colourless, odourless, non-corrosive liquids that contain no phosphates or bromine.
Where biguanides are used:
Biguanide chemicals are synthetic compounds used in pools and spas to stop combined chlorine (chloramines) forming, which is what irritates swimmers' eyes, nose, throat and skin.
Where they come from:
The bigu- part comes from biguanidine hydrochloride monohydrate, a biguanide compound that has been used across many industries since the 1880s.
Being colourless, odourless and free of phosphates and bromine makes them popular with owners who want more eco-friendly chemicals in their pools and spas.
How they work:
As chlorine stabilisers, biguanides prevent chloramines forming, the very thing that makes poorly balanced pools and spas irritating to the eyes, nose, throat and skin.