Bio-Dex Instant Action Spa Knock Out Metal Stains Max for plaster and fiberglass Hot Tubs, Spa and Fountains. It goes to work immediately and swimming can resume 4 hours after application with continuous filtration.

Removes Copper, Iron and Black Cobalt Stains from fiberglass, and
plaster pools, spas and fountains.

Removes and Prevents some of the most difficult metal stains.

Spa Knock Out Metal Stains Max
is an excellent aid for the removal of metal
stains from Pools, Spas, Fountains and other water features. It is
stable at high temperatures and is unaffected by chlorine, acid or other
sanitizing chemicals and quickly goes into solution with pool water.

Directions for use based on 500 gallons of water:
(Recommended application: to apply at night after using the spa)
Re-entry after stain treatment wait time of 8 hours)

1. Adjust pH to 6.8 to 7.2 for best results.
2. With the filter off, add 2oz Stain Remover Max per 500 gallons of spa
water and circulate for 5 minutes.
If stain persists after 48 hours, repeat treatment.

Wait 8 hours before entering the spa.

Metal Stain Remover can also be used directly on stains when water has
been drained or in a mix along with Bio-Dex Plaster White 'n Brite. 
(see website for additional information on acid washing)

Maintenance Dose:  Add 1oz per week per 500 gallons as needed.
Maintain pH level between 7.2 and 7.6.

Download the Safety Data Sheet