Updated: Feb 25, 2022
In most cases, excessive sanitizer will not permanently damage the operation of your hot tub, but it will accelerate wear and tear on certain components, which are replaceable. (Plus, damage obviously caused by overdosing can void the warranty.) Common examples include:
Cosmetic decals/appliques discoloring, bubbling or peeling.
Foam headrests/pillows deteriorating or blistering, especially near the water line (pictured middle).
Rubber seals or gaskets inside of diverter valves wearing out prematurely.
Valve covers appearing dull or faded.
Jet faces below the water line appearing dull or faded compared to jet faces above the water line.
Hot Tub Cover becoming discolored or “bleached” underneath in a short period of time.
Stainless steel parts rusting or pitting.
Too much sanitizer can cause some discomfort with your eyes or skin. This could also dry out your hair or leave a strong chemical smell. You might also notice some fading in your swim suits.
Several different sanitizers are approved for hot tub use. But you may prefer one over another, perhaps due to sensitive skin. Target levels are measured in parts-per-million (ppm) using the appropriate test strip:
Chlorine (dichlor) has been in use the longest, but is less preferable for people with sensitive skin. Using six-in-one test strips, the target level for “free chlorine” is between 3-5 ppm. Free chlorine above 5 ppm is too high.
Bromine is more stable in hot water than chlorine. It is available in granules, or automatic slow-dosing cartridges which are preferable for people with sensitive skin. Using six-in-one test strips, the target level for bromine granules is between 4-6 ppm. Using Frog® Serene® test strips for bromine dual-cartridge (in-line or floating) systems, the target level is between 1-2 ppm. Bromine above 6 ppm is too high.
SmartChlor® is the latest sanitizer developed. Due to its unique molecular structure, it remains effective at lower concentrations than bromine or chlorine. In the United States, it is available in automatic slow-dosing cartridges which are preferable for people with sensitive skin. Using Frog @ease® test strips, the target level for Smartchlor dual-cartridge (in-line or floating) systems is between 0.5 to 1 ppm. This translates to a light green color reading on the test strip.
Never use TriChlor tabs or calcium hypochlorite “cal hypo” in your spa.
· Why not use cal hypo in a spa? Due to its high calcium component and high pH level, it tends to form deposits on spa heater parts and plumbing fittings, and may also leave an unattractive film or ring at the hot tub’s water line. It is one of the most caustic forms of chlorine on the market, so avoid it in spas.