Spa water has a persistent musty or moldy odor despite chemical treatment.

Safety: Wear gloves and eye protection when handling spa chemicals.

• Shock treatment: Superchlorinate the spa according to Beachcomber chemical guidelines and run all pumps with air controls open.
• Use a plumbing purge: Add a spa plumbing purge product and circulate per instructions to break down biofilm.
• Drain and refill: After purge, drain the spa completely, wipe the shell, clean or replace the Microfilter, and refill with fresh water.

Maintain proper sanitizer and change water every 3–4 months to prevent recurrence.