How to Deal With Algae in a Hot Tub

Even with proper maintenance, algae can appear in a hot tub due to warm water, improper sanitation, and poor circulation. Understanding the causes helps you address the problem effectively.

Common Causes of Algae Growth

• Low sanitizer levels that let algae thrive

• Poor water circulation and stagnant areas

• Warm, sunny conditions combined with uncovered water

• Infrequent cleaning or filter maintenance

Tools and Supplies You Will Need

Before starting, gather the supplies you will need to remove the algae and restore water clarity.

Basic Supplies

• Hot tub shock (chlorine or non-chlorine)

• Spa brush or soft sponge

• Test strips or a water test kit

• Clean filter or filter cleaner

• Skimmer net

Optional Extras

• Algaecide made for hot tubs

• Microfiber towel for drying surfaces

• Protective gloves

Step-by-Step Guide to Removing Algae

Follow these steps to clean your hot tub and get rid of algae effectively.

Step 1: Drain the Water

• Turn off the hot tub and drain all the water completely.

• Use a wet vacuum to remove water from hard-to-reach areas.

Step 2: Clean the Shell

• Use a spa brush or sponge with a non-abrasive cleaner to scrub the interior shell.

• Pay special attention to corners, seats, and jets where algae hides.

• Rinse thoroughly with clean water.

Step 3: Clean or Replace the Filter

• Remove the filter and clean it using a filter cleaner or hose.

• If the filter is very dirty or old, replace it with a new one.

Step 4: Refill and Balance the Water

• Refill the hot tub with fresh water.

• Test and balance pH, alkalinity, and sanitizer levels.

• Ideal sanitizer level for chlorine is 1–3 ppm and for bromine is 3–5 ppm.

Step 5: Shock the Water

• Add a spa shock to kill any remaining algae spores.

• Leave the cover off for a few hours to let gases escape.

Advanced Tips to Prevent Future Algae Growth

Improve Circulation

• Run the jets and circulation system daily to keep water moving.

• Make sure all jets and valves are open and functional.

Cover Your Hot Tub

• Use a properly fitting cover to block sunlight and debris.

• Check the cover for tears or damage and replace if necessary.

Maintain Regular Cleaning

• Wipe down the shell weekly.

• Rinse and clean the filter monthly.

• Drain and refill the hot tub every 3–4 months.

Common Mistakes to Avoid

• Using household cleaners that can damage the shell or cause foaming

• Neglecting the filter, which traps debris and contaminants

• Adding too much sanitizer, which can harm surfaces and irritate skin

Safety Tips While Cleaning

• Always turn off power before draining and cleaning.

• Wear gloves to protect your skin from chemicals.

• Keep children and pets away from the area while cleaning.

Helpful Notes

• Monitor water chemistry regularly to prevent algae from returning.

• Keep a maintenance log to track cleanings, water changes, and chemical additions.

• If algae keeps coming back, consult a professional to check for hidden problems.

By following these steps and staying consistent with your maintenance, you can keep your hot tub free from algae and ready for safe, relaxing use any time you want.