The only way to lower TDS is to drain and refill the hot tub with fresh water. High TDS can lead to cloudy water, scaling, and reduced chemical effectiveness, so it’s important to monitor and manage TDS levels.

Why does TDS matter in a hot tub?

High TDS reduces sanitizer effectiveness and makes water look dull or cloudy. Keeping TDS low helps maintain clear, safe, and inviting water.

What is TDS and Why Does it Increase?

What is TDS?

TDS, or Total Dissolved Solids, refers to the combined minerals, salts, metals, and organic matter dissolved in the water. Over time, these solids accumulate and make water harder to maintain.

What contributes to TDS?

• Sweat, body oils, lotions, and cosmetics

• Chemicals like chlorine, bromine, shock, and clarifiers

• Minerals from tap or well water

• Debris like dust, leaves, and other contaminants

When TDS levels rise too high, water becomes less responsive to chemical adjustments and loses its sparkle.

Signs of High TDS

• Cloudy or hazy water

• Foam or scum forming on the surface

• Sanitizer tests show normal levels, but water remains unsanitary

• Water feels sticky or has an unpleasant texture

Why High TDS is a Problem

Poor Sanitizer Performance

When dissolved solids accumulate, chlorine or bromine struggles to keep up. This allows bacteria and algae to thrive.

Cloudy or Dull Water

Excess solids scatter light, leaving water looking flat, unappealing, or milky.

Stress on Equipment

High TDS can lead to scale buildup, corrosion, and clogging of filters and plumbing, which shortens the life of your hot tub components.

How to Measure TDS

Using a digital TDS meter is the most accurate way to check levels. You can also have water tested at a spa store.

Recommended TDS levels

• Below 1500 ppm: Ideal

• 1500 to 2000 ppm: Caution zone

• Above 2000 ppm: Time to drain and refill

Test monthly so you can address rising TDS before it becomes a bigger problem.

Steps to Lower TDS

1. Drain and Refill the Hot Tub

Since TDS represents all dissolved substances in the water, replacing old water with fresh is the only way to significantly reduce it.

How to drain and refill

1. Turn off power to the spa.

2. Attach a hose to the drain valve and empty the tub completely.

3. Clean the shell with a non-abrasive cleaner.

4. Rinse thoroughly to remove residue.

5. Refill with clean, filtered water.

6. Balance chemicals before use.

Draining every 3 to 4 months keeps TDS under control.

2. Use a Hose Pre-Filter

A hose pre-filter removes metals, minerals, and other impurities from your source water, helping reduce starting TDS.

Benefits of a pre-filter

• Cleaner water from the start

• Extends time between water changes

• Reduces demand on chemicals

3. Maintain Proper Water Balance

Keeping pH, alkalinity, and sanitizer in the recommended range slows down TDS buildup.

Target ranges

• pH: 7.4 to 7.6

• Alkalinity: 80 to 120 ppm

• Chlorine: 1 to 3 ppm

• Bromine: 3 to 5 ppm

Test water at least twice a week to catch imbalances early.

4. Encourage Rinsing Before Soaking

One of the biggest contributors to TDS is what people bring into the hot tub on their skin and swimwear.

Simple ways to reduce contaminants

• Post a sign asking guests to shower before soaking

• Provide clean towels and slippers

• Avoid wearing lotions, makeup, or perfumes in the spa

5. Limit Chemical Overuse

More chemicals do not necessarily make the water cleaner. Overdosing only adds to TDS without solving problems.

Tips for smart chemical use

• Follow label directions carefully

• Shock only when needed

• Avoid unnecessary clarifiers or algaecides

Long-Term Tips to Control TDS

Establish a Regular Maintenance Routine

A consistent routine keeps your water clean and balanced while preventing solids from building up too fast.

Suggested schedule

• Weekly: Test and adjust water, rinse filters

• Monthly: Deep clean filters and check TDS

• Quarterly: Drain and refill water, inspect components

Use Enzyme Products

Enzyme-based products break down organic material, helping your sanitizer work more efficiently and slowing TDS buildup.

Advantages of enzymes

• Reduces need for shock

• Keeps water clearer longer

• Less stress on filters and sanitizer

Keep the Hot Tub Covered

Covering your hot tub when not in use prevents debris, insects, and rainwater from contaminating your water.

Benefits of a good cover

• Minimizes evaporation and chemical loss

• Keeps out dust, pollen, and leaves

• Reduces heating costs

When to Call a Professional

Sometimes even after draining and cleaning, water balance issues persist. In such cases, expert help may be needed.

When to contact a technician

• TDS rises quickly even after refill

• Water remains cloudy or foamy despite maintenance

• Equipment shows scaling, corrosion, or leaks

• Internal plumbing may need deep cleaning

A professional can perform thorough testing, inspect components, and recommend advanced solutions to restore your spa to perfect condition.

Enjoy Fresh, Clean Water Every Time

By understanding TDS and how to manage it, you can extend the life of your hot tub, keep water looking beautiful, and make each soak more enjoyable. Combine regular draining with smart maintenance, proper balance, and preventative steps for the best results every time you step into your spa.