Hot Tub Chlorine

When it comes to swimming pools, chlorine is the sanitizer of choice for most owners. It is relatively inexpensive and when maintained at proper levels, keeps your water crystal clear. When deciding how to sanitize your hot tub, some new owners may assume that chlorine is the default choice. Before you make the leap, here is some good information about hot tub chlorine.


About Chlorine

Chlorine is a member of the same chemical family as bromine—another common hot tub sanitizer. This chemical family is referred to as halogens and attacks microorganisms like bacteria and uses oxidation to eliminate them. This effective method of sanitation makes them both popular choices.

While super useful in pools, chlorine is less effective than its family member, bromine, due to the high temperatures in spa water. Chlorine also doesn’t typically come in tablet form and doesn’t have a slow release like bromine, meaning you have to test and dose the water more frequently.


Types of Hot Tub Chlorine

If you do use chlorine as your primary sanitizer, you have a few different options:

Sodium Dichlor Granules

Dichlor is really the only packaged chlorine form that is suitable for spas, albeit a bit more expensive than some other options. It is nearly pH neutral and doesn’t need the addition of a stabilizer like cyanuric acid. It’s RECOMMENDED that dichlor is mainly used as a hot tub shock because it doesn’t come in tablet form like bromine. It is fairly stable in the high temperature of hot tub water and is best in the fine granular formulation that will dissolve quickly in the water. The large pellet version takes too long and can damage the acrylic if it accumulates along the bottom of the tub. One of the cons of this form is that you need to dose and test the water more frequently because it doesn’t come in a time-release tablet or a sanitizer cartridge.

The best way to use granulated chlorine is to dissolve it in a bucket of water first and THEN add it to the water. Sometimes putting granules directly into the spa can discolor the acrylic. NEVER add other spa chemicals into the bucket with the chlorine—mixing chemicals in general is a bad idea. Just stick with adding one at a time.

Salt Chlorine

You can chlorinate the water using some alternative methods like the Solaxx Saltron Mini—an easy to install system for hot tubs that produce chlorine from mineral salts. This little generator can be installed without having to modify the spa and adapts the popular salt chlorine pool technology accessible for spa owners.

Types of Hot Tub Chorine to Avoid

Trichlor Tablets

Trichlor tablets are another form of chlorine that is great for pools but is not recommended for use in spas. It is highly acidic and dissolves too slowly to be effective. When the tabs come in contact with the acrylic shell for extended periods of time, it’s been known to bleach or discolor the surface. It may even cause a permanent ring along the water line.

Calcium Hypochlorite (Cal-Hypo)

This type of chlorine is another one that is popular for pools because it is relatively inexpensive, but it needs cyanuric acid to stabilized, otherwise it’ll lose 95% of its effectiveness in just a few hours in the heat of the hot tub. It has a high concentration of calcium, a high pH, and can form deposits on spa heater parts, plumbing fittings, and leave a harsh ring. It’s better to spend a little more money on the dichlor than save money on the cal-hypo, but ultimately harm your equipment.

Sodium Hypochlorite

Otherwise known as household beach, it’s best to leave this indoor. While some may think it’s a good idea to use it for hot tub sanitation purposes, it’s really harsh on your pH balance and has an aggressive odor.

Hot Tub Chlorine Tips

If you do go with chlorine instead of bromine, just make sure you check your water chemistry often and keep everything balanced. Be careful not to let your sanitizer levels dip, otherwise you’ll be dealing with a nasty bacteria problem that may lead to itchy skin or red eyes. You want your levels to stay between 1.5-3.0 parts per million (ppm). You may be costing yourself some time if you choose chlorine as your sanitizer, but when used properly it will keep your water clean and clear.

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