Water Maintenance

Keeping your water clean, clear and balanced is the most important part of owning a cold plunge. Follow this guide to protect your unit, extend water life, and ensure every session is safe and hygienic.

Important: Wait 15 minutes between adding each chemical. Always add chemicals with the unit running so they circulate evenly. Do not plunge for 30 minutes after adding any chemical.

Shower before use. Body oils, lotions and sweat are the primary cause of water degradation. A quick rinse before every session significantly extends water life and chemical balance.

What you need

• Non-foaming chlorine granules (do not use foaming pool chlorine as it will damage the pump)
• pH reducer (Spa Down or equivalent)
• pH increaser / alkalinity buffer (Spa Up or equivalent)
• Water test strips (chlorine, pH and alkalinity)

A starter kit including all of the above is available from our accessories store or by contacting us directly.

After every drain and refill

This protocol should be followed every time you change the water.

Core (approx. 300L)

1. Fill with fresh tap water
2. Test pH and alkalinity using test strips. Adjust using the tables below before adding chlorine
3. Add 3g of chlorine granules (approx. 1g per 100L)
4. Run the unit for 30 minutes before plunging

Pro (700L)

1. Fill with fresh tap water
2. Test pH and alkalinity. Adjust as needed
3. Add 7g of chlorine granules
4. Run the unit for 30 minutes. The ozone system will activate during circulation

Elite (capacity dependent on fill level)

1. Fill with fresh tap water
2. Test pH and alkalinity. Adjust as needed
3. Add 7 to 10g of chlorine granules depending on fill level
4. Run the unit for 30 minutes before plunging

Weekly maintenance

1. Test water chemistry with test strips
2. Adjust chlorine, pH and alkalinity using the tables below
3. Wipe the waterline with a clean sponge if a residue line is forming
4. Rinse the filter cartridge under clean running water
5. Clear any debris from the filter strainer

Weekly dosing reference tables

Chlorine

pH

Alkalinity

How often should I change the water?

Change sooner if: water is cloudy or discoloured, there is a persistent odour despite chemical treatment, biofilm appears on tub walls (slippery feeling), or chlorine reads zero despite repeated dosing.

Full water change procedure

1. Power off the unit and unplug from the socket
2. Drain the tub using the drain port or a submersible pump
3. Wipe down the interior with a clean dry cloth. Do not use soap or bleach
4. Rinse thoroughly with clean water, drain again
5. Replace or rinse the filter cartridge before refilling
6. Refill with fresh tap water
7. Reconnect and power on
8. Follow the after-drain chemical protocol above
9. Run for 30 minutes before first plunge

Filter maintenance

Pro and Elite models have a dual-stage filter. Both stages should be rinsed at the same time. Replace both simultaneously at the 3-month mark.

What to avoid

• Never use foaming chemicals as they damage the pump and will void your warranty
• Never use household bleach directly. Use granular chlorine designed for plunge or hot tubs
• Never add chemicals while anyone is in the tub
• Do not let pH fall below 7.0. Corrosive to the unit and uncomfortable on skin
• Do not leave water stagnant. Run the unit continuously. Stagnant water allows biofilm to form inside the pipework, requiring a deep clean to resolve

Signs your water needs attention

• Visible cloudiness or colour change
• Persistent smell that doesn't clear after chemical dosing
• Slippery or slimy feeling on tub walls (biofilm)
• Chlorine reads zero despite repeated treatment
• Skin irritation after plunging

Need help?

Water chemistry questions are one of the most common things our team helps with. Don't guess, just ask.

WhatsApp us for the fastest response, 7 days a week. Email: hello@thermoxrecovery.com