FROG Serene® (Bromine) Cartridge - Purple 7.1 oz - 33% More Bromine Compared to Yellow Cartridge Oxidizer you can use either the

you can use either the yellow

Spa Frog Serene

Rento Midsummer Birch Sauna Scent - Sauna Aromatherapy - Enjoy the summery fragrance of fresh birch leaves while relaxing in the sauna

Iron will typically cause rust colored stains

protecting your pH from sudden swings and making every other step in water care work better

FROG Serene® (Bromine) Cartridge - Purple 7.1 oz - 33% More Bromine Compared to Yellow Cartridge Oxidizer you can use either theThe FROG Serene (Bromine) Cartridge is for use in the Serene In Line System for hot tubs and spas. This purple bromine cartridge contains 33% more bromine than the standard yellow bromine cartridge. Size: 7. 1 oz The Serene (Bromine) cartridge is the active sanitizer in this system. Use in combination with the FROG blue Mineral cartridge, found here. Not sure how to maintain or start up your hot tub on this system? Download the FROG Serene (bromine)