Why Water Maintenance Matters
Clean water is not just about aesthetics. Poorly maintained cold plunge water can harbor bacteria, cause skin irritation, and damage your equipment. Fortunately, maintaining clean cold plunge water is straightforward once you understand the basics.
The Three Pillars of Clean Water
1. Filtration
Filtration removes physical particles like skin cells, hair, dirt, and debris from the water. Most chiller-equipped cold plunges include filtration rated at 20 to 150 microns. Replace or clean filters according to the manufacturer schedule, typically every 2 to 4 weeks for heavy use.
If your setup does not include filtration (common with budget and DIY cold plunges), add an inline filter between your tub and chiller. The Penguin Chillers filter kit is a popular aftermarket option.
2. Sanitization
Sanitization kills bacteria and prevents biological growth. The three main approaches are:
Chlorine or bromine: Traditional pool chemicals. Effective and inexpensive. Maintain 1 to 3 ppm free chlorine. Can cause skin irritation at high levels.
Ozone (O3): Used by premium cold plunges including Morozko Forge and Renu Therapy. Ozone generators inject O3 into the water, which kills bacteria on contact. No residual chemicals in the water.
UV sanitation: Ultraviolet light kills bacteria as water passes through the UV chamber. Often combined with ozone for maximum effectiveness.
3. pH Balance
Maintain pH between 7.2 and 7.6 for comfortable water that does not irritate skin or corrode equipment. Test weekly with pool test strips. Use pH Up or pH Down products to adjust.
Weekly Maintenance Checklist
Test pH and sanitizer levels with test strips. Clean skimmer basket and tub rim. Add sanitizer as needed. Check water clarity.
Monthly Maintenance
Clean or replace filter cartridge. Shock the water with non-chlorine oxidizer. Wipe down the tub interior above the waterline. Clean the insulated cover.
When to Change the Water
With good filtration and sanitization, water can last 3 to 4 months before a full drain and refill. Change sooner if water becomes cloudy despite treatment, develops an odor, or if pH becomes difficult to balance.
Cold Water Advantage
Cold water naturally inhibits bacterial growth much better than warm water. This is one reason cold plunges require less maintenance than hot tubs. Most bacteria that cause recreational water illness thrive at warmer temperatures and struggle below 50 degrees Fahrenheit.
