Cold Plunge Water Cloudy or Foamy
easy 30–60 min
Tools: test strips (chlorine or bromine, pH, alkalinity), soft sponge or microfibre cloth, bucket · Materials: spa sanitizer matching your tub (chlorine granules or bromine), non-foaming spa cleaner, replacement filter cartridge if yours is over a year old
Steps
- Test the water: with free chlorine below 1 ppm (or bromine below 2 ppm) and pH outside 7.2–7.6, the cloudiness is a sanitizer problem before it is a filter problem.
- Pull the filter cartridge, rinse it with a hose from the inside out, and soak it overnight in filter cleaner; body oils on the pleats are what let foam through.
- Wipe the waterline and walls with a spa cleaner and a soft cloth — the slimy film is biofilm, and sanitizer cannot reach it while it is stuck to the surface.
- Shock the water with a non-chlorine or chlorine shock as the label directs, run the pump for 12 hours with the lid off, and retest.
- Ask everyone to rinse off before plunging — a 20-second shower removes most of the lotion and sweat that feeds the foam.
- If the water is still hazy after 48 hours of correct chemistry, drain, wipe the shell and the drain fitting, and refill; cold tubs are small enough that a refill is cheaper than fighting old water.
Stop and call a pro if
- the pump hums but does not move water, or trips the breaker
- foam returns within a day of a fresh fill — biofilm inside the plumbing needs a line flush
- anyone has had a rash or ear infection after using the tub
What a pro does that you can't
A spa technician flushes the plumbing lines with a biofilm remover, checks the pump and ozonator, and sets up a dosing routine that matches how often you use the tub.
DIY cost: $15–40 in test strips, shock and cleaner