HotSpring Spa Clean Screen Prefilter. The best way to deliver easy-to-manage, longer-lasting hot tub water is to start with the cleanest water possible. This can be achieved with the new Clean Screen pre-filter. This one-of-a-kind pre-filter traps organic contaminants, metals (such as copper and iron), and tannins before they are introduced into the spa, so the water is as clean as possible at start-up. Another benefit of the Clean Screen pre-filter is that it does not contain silver ions, so it can be used with any chlorine, bromine, or biguanide water care program. Removing contaminants prior to introducing water into the spa helps decrease the need for additional chemicals that would otherwise be needed to treat the water. Adding fewer chemicals means less work for every hot tub owner. Additionally, reduced chemical use can contribute to a lower Total Dissolved Solids (TDS) level, which may help to extend the life of the water – so water changes are less frequent.