Most spas are sold with ozone.  At 3-5 years, the spa water starts degrading.  Water chemistry suddenly gets harder to balance, and the chemical usage goes up.  Time to replace your spa ozone generator!

Ozone is a natural, powerful oxidizer which destroys 99.99% of viruses and bacteria. It breaks down oils and helps rid the spa of metals and other tiny particles.  What's left is healthy water that is easy to balance with fewer chemicals and less fuss.