Terry Arko has more than 40 years’ experience in the recreational water industry, working in service, repair, retail sales, chemical manufacturing, technical service, commercial sales, and product development. He has written over 100 published articles on water chemistry. He is a member on the board of the Recreational Water Quality Committee (RWQC) and the California Pool and Spa Association (CPSA). He is also a Certified Pool Operator(CPO) instructor with the Pool Hot Tub Alliance (PHTA) and an instructor for the Pool Chemistry Training Institute (PCTI) Pool Chemistry Certified Residential Course. Terry is currently working as Technical Content and Product Training Manager for HASA Pool, makers of HASA Sani-Clor. He can be reached at terryarko@hasapool.com.