What Turns the Water in Your Hot Tub Green? Causes and Solutions

Opening your hot tub to find green water can be disheartening and alarming. It not only spoils the relaxing experience but also indicates a potential chemical imbalance that could affect your health and the longevity of your hot tub. In this blog, we will explore why hot tub water turns green, how to fix it, and preventive measures to ensure your hot tub stays crystal clear.

What Causes Green Hot Tub Water?

1. Algae Growth Due to Lack of Sanitizer

The most common reason for green hot tub water is algae growth. Algae thrive in environments where sanitizer levels (chlorine or bromine) are insufficient. This can happen due to:

• Neglecting regular water maintenance
• Heavy hot tub usage that depletes sanitizer quickly
• External factors affecting sanitizer efficiency

When the sanitizer level drops, algae spores present in the water can multiply rapidly, turning the water green.

2. Excessive Metals in the Water

If your hot tub water maintains balanced sanitizer levels but still appears green, the culprit might be excessive metals. Metals such as copper and iron can enter the water from:

• The source water supply
• Hot tub components like pipes and fixtures

When these metals oxidize, they give the water a green tint.

How to Clear Green Water from Your Hot Tub

1. Shock the Water and Clean Filters

To eradicate algae and restore clarity:

1. Shock the Water: Add a high dose of chlorine or bromine granules to elevate the sanitizer level above 10 ppm. Leave the hot tub cover off for at least 20 minutes to prevent damage.
2. Clean the Filters: After a few hours, clean or replace the hot tub filters to remove dead algae and other contaminants.

2. Drain and Refill

If shocking doesn’t clear the water:

1. Drain the Hot Tub: Empty the hot tub completely.
2. Clean the Pipework: Use a pipe flush cleaner to eliminate any algae hiding in the plumbing.
3. Refill with Fresh Water: Refill the hot tub, ensuring the sanitizer level is immediately brought to 5 ppm.

Preventing Green Water in Your Hot Tub

1. Regular Water Maintenance

• Maintain chlorine/bromine levels between 3-5 ppm.
• Keep the pH between 7.2-7.6 and alkalinity between 80-120 ppm.

2. Use a Pre-Filter

• Use a pre-filter when filling the hot tub to remove metals from the source water.

3. Clean the Filters Regularly

• Regularly clean and degrease the filters to ensure effective filtration and sanitization.

4. Drain and Refill Periodically

• Drain and refill your hot tub every 3-4 months. Use a pipe flush to remove biofilm that can harbor algae and bacteria.

Keeping Your Hot Tub Water Algae Free

Maintaining a clean and healthy hot tub is crucial for an enjoyable and relaxing experience. By understanding the causes of green hot tub water and implementing effective solutions, you can ensure your hot tub remains inviting and safe. For a more comprehensive guide on keeping your hot tub in top condition, be sure to check out our Hot Tub Maintenance Checklist. This guide covers everything you need to know about regular maintenance routines, essential products, and expert tips to keep your hot tub running smoothly all year round. Now that your hot tub is no longer green you may be asking yourself the question why is my hot tub foaming? Learn why In our comprehensive article on why do hot tubs foam.

Frequently Asked Questions

How often should I shock my hot tub to prevent green water?

It's recommended to shock your hot tub at least once a week, or after heavy usage, to maintain clear and sanitized water.

Can I use household bleach to shock my hot tub?

It’s best to use products specifically designed for hot tubs, as household bleach can be too harsh and might not be safe for the hot tub materials and your skin.