Hello, at my plant we use 50% caustic soda solution we receive in chemical totes. We then feed the 50% to a Merlin dilution system where it gets batched to 20%. We then pump the 20% caustic solution using an encore diaphragm pump through our valve board and into our source main through an injection quill. We usually use between 80-100lbs of caustic in our batching system per day. My pH readings have been fluctuating anywhere from 6.95-7.10when we usually run around 7.38 I’ve checked my analyzer calibration. Checked my pump, checked the dilution system programming and even replaced the feed line and injection quill with no luck. My question is, how am I using more pounds of caustic per day, (150lbs per day now) but my pH is way down from normal? Thanks in advance.