How often should I change my cold plunge water?

With proper filtration and sanitization, personal-use cold plunges (1-2 people) need a full drain and refill every 3-4 months. Shared or high-frequency use systems should be drained monthly. Always drain and refill if water chemistry becomes difficult to balance or develops an odor.

Can I use hot tub chemicals in my cold plunge?

Most hot tub chemicals work in cold plunges, but dosing is different. Chlorine is more effective in cold water than bromine, so chlorine is the preferred sanitizer for cold plunges. pH adjusters, alkalinity increaser, and calcium hardness products are the same. Avoid using hot tub "shock" products designed for high temperatures.

Why is my cold plunge water cloudy?

Cloudy water usually means one of three things: sanitizer level is too low (bacteria growth), the filter needs cleaning or replacement, or the water chemistry is out of balance (especially high pH or low alkalinity). Test your water, clean the filter, and adjust chemicals. If it does not clear within 24 hours, drain and refill.

Cold Plunge Maintenance: A Complete Guide

A cold plunge tub is only as good as its maintenance routine. Without proper water care, you'll deal with cloudy water, bacteria growth, and equipment failures. The good news: cold plunge maintenance is straightforward once you have a routine. Here's everything you need to know.

Common Scenarios

New cold plunge owner setting up a routine

You just had a cold plunge installed and want to keep it clean. The key is establishing a simple weekly routine: test water chemistry 2-3 times per week, rinse the filter weekly, and keep sanitizer levels consistent.

Water turned green or has an odor

Your water was clear last week but now has a green tint or smell. This means sanitizer levels dropped and bacteria or algae got a foothold. Shock treat the water, clean the filter, and if it doesn't clear within 24 hours, drain and start fresh.

Seasonal adjustments in warm climates

In hot states like Texas and Florida, your chiller works harder in summer and warm water promotes faster bacteria growth. You may need to increase sanitizer levels and run the filter pump longer during warm months.

Water Treatment Basics

Cold water inhibits bacteria growth compared to warm water (like hot tubs), but it doesn't eliminate it. You still need some form of sanitization:

Chlorine or Bromine

The most common and affordable option. Maintain free chlorine at 1-3 ppm or bromine at 2-4 ppm. Test water 2-3 times per week with test strips. Chlorine is more effective in cold water than bromine, making it the preferred choice for most cold plunge owners.

Ozone

Ozone generators kill bacteria and break down organic matter without chemical residue. Many higher-end cold plunge systems include a built-in ozone system. You may still need a small amount of chlorine as a backup sanitizer.

UV Sanitization

UV-C lights installed in the plumbing loop kill bacteria as water passes through. Like ozone, UV is chemical-free but works best paired with a low-level residual sanitizer.

Filtration

Your cold plunge should have a filtration system that runs continuously or on a timer. Most systems use cartridge filters similar to hot tub filters.

Rinse cartridge filters weekly with a garden hose
Deep clean filters monthly by soaking in filter cleaning solution
Replace filters every 3-6 months depending on usage
Check for debris in the skimmer basket if your system has one

Water Chemistry

Beyond sanitizer levels, keep these parameters in check:

pH: 7.2-7.6 (slightly alkaline). Low pH corrodes equipment; high pH reduces sanitizer effectiveness.
Total alkalinity: 80-120 ppm. Buffers pH fluctuations.
Calcium hardness: 150-250 ppm. Too low damages equipment; too high causes scale buildup.

Test weekly with a liquid test kit or test strips. Adjust with pH up/down, alkalinity increaser, or calcium hardness increaser as needed.

Chiller Maintenance

The chiller is the most expensive component in a cold plunge system. Keep it running efficiently:

Keep the area around the chiller clear for airflow (12+ inches on all sides)
Clean condenser coils monthly — dust and debris reduce cooling efficiency
Check refrigerant lines for frost buildup (indicates a problem)
Ensure the water pump is running properly — low flow can damage the chiller
Have a professional service the chiller annually

Drain and Refill Schedule

Even with good filtration and chemistry, you should drain and refill your cold plunge periodically:

Personal use (1-2 people): Every 3-4 months
Shared or frequent use: Monthly
Commercial: Follow local health department guidelines

When you drain, scrub the interior surfaces, clean the plumbing lines with a pipe-flush product, and inspect seals and fittings for wear.

Need Help with Your Setup?

A properly installed cold plunge with good filtration and plumbing makes maintenance much easier. If you're planning a new installation or need service on an existing system, browse Cold Plunge Install Pros to find qualified installers in Texas, Florida, and North Carolina.

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