Hello! I am a relatively new CPO charged with two of the older tile pools at the Holland Aquatic Center in Holland Michigan. I need some help to understand why I need to add so much bicarb to maintain my Alkalinity over 50. I have an Instructional Lap pool, 75' x 45', 3375 sqft, 113,902 gal, hybrid sand filter, turnover 5.4 hrs, recirculation rate 320 gpm, and a surge capacity of 2,047 gal. The dive well is 45' x 25', 1125 sqft, 105,465 gal, hybrid sand filter, turnover 7.6 hrs, recirculation rate 280 gpm and a surge capacity of 1075 gal. I use liquid sodium hypochlorite and liquid muriatic acid fed via pump and controled by prominent (lap pool) and siemens (dive) controllers. My raw incoming water has an alkalinity of 120ppm but I can't keep the alkalinity of the dive and lap pools over 70 without adding 50lb bags of Sodium Bicarbonate ever 2-3 weeks. None of the other pools in my complex have this issue and I would like to find the root of the problem. Please contact me if you have any advice!