You may or many not have realized it yet, but what is taught here about pool and spa care, greatly contradicts pretty much the rest of the industry who use little or no chemistry, or in some instances, teach vudu chemistry in their advice to DIY'ers and professionals alike. The most significant of these contradictions in methodologies has to do with TFP's insistence on the importance of maintaining the CYA level in pools sanitized with chlorine within a suitable and manageable range and easily and cheaply maintaining that suitable range by mostly using only liquid chlorine or an SWCG instead of trichlor pucks and other chlorine forms that constantly add to the CYA level. And also, to go along with keeping CYA within a suitable range, the insistence here of maintaining a ratio of your FC to your CYA at all times to ensure pools are maintained clean, clear, and safe. Not only does the industry ignore these cya and fc ratio principles, but when they hear or read about them, they believe that these all-important TFP tenets are not all that important, not worth doing, and instead they mostly focus on fixing green and cloudy pools as their methodologies of care regularly fail their clients. Many in the industry believe that TFP is too "sciencey", too picky, and not necessary; but these tenets of proper pool care are chemistry principles that have been shown to be true via chemistry formulas by the great Chem Geek and others here past and present, and they are easy and cheap to manage once learned.