Spa water has a persistent musty or moldy odor.

Safety first: Avoid using the spa until water quality is restored; contaminated water can cause skin and respiratory irritation.

• Step 1 – Test and balance water: Use a test kit to check sanitizer (chlorine/bromine), pH, and alkalinity. Adjust to Nordic-recommended levels.
• Step 2 – Shock treatment: Add a spa shock product per label directions to oxidize organic contaminants.
• Step 3 – Clean or replace filter: Remove the Nordic filter cartridge, clean thoroughly, or replace if old or heavily soiled.
• Step 4 – Flush plumbing: Use a spa plumbing flush product designed to remove biofilm. Circulate per instructions, then drain the spa completely.
• Step 5 – Clean shell and cover: Wipe down the shell with a spa-safe cleaner. Clean the underside of the cover and allow it to dry fully.
• Step 6 – Refill and maintain: Refill with fresh water, balance chemicals, and maintain proper sanitizer levels to prevent recurrence.