FreshWater Ag+ Silver Ion Sanitizer | Hot Tub

The FreshWater Ag+ Silver Ion Sanitizer is a supplemental sanitizing cartridge that slots into your spa's filter standpipe and releases a steady stream of positively-charged silver ions into the water for approximately four months. Those silver ions inhibit bacterial growth continuously, meaning you can run your spa on a much lower chlorine residual than a chlorine-only spa would require.

This is one of the most popular FreshWater products because it solves a real comfort problem: high chlorine smell. Owners running a chlorine-only system often complain about strong sanitizer smell, dry skin, irritated eyes, and faded swimsuits — all caused by maintaining enough chlorine to handle bacteria and oxidize organic contaminants single-handedly. Add an Ag+ cartridge, and the silver ions handle most of the bacterial inhibition. You still need chlorine or MPS for oxidation (more on that below), but you need a lot less of it.

Important to understand before you buy: Ag+ is a supplemental sanitizer, not a complete replacement for chlorine. Silver ions inhibit bacteria but do not oxidize body oils, sunscreen, sweat, or other organic load brought in by bathers. You still need to add a small amount of dichlor or MPS (non-chlorine shock) regularly to oxidize organics and keep water clear. Owners who skip this step end up with cloudy water and assume the cartridge is defective — it isn't. The two-part approach is how the system is designed to work.