Condensate tray bacterial control. StayClean Tablets are an inexpensive, easy-to-use condensate tray treatment. The tablets will control odours and prevent sludge build-ups and blockages in the condensate tray and drain. They are safe to use, non-corrosive and, being totally soluble, leaving no residues to create further problems. One tablet will treat a 2-3kW system and will last up to 8 weeks. Multiple tablets can be used in larger systems for maximum flexibility.