A few weeks ago I refilled my 40,000 gallon IG pool. Pool company told me to add 12 lbs of Nu-clo Conditioner & Stabilizer (consistent with Nu-Clo directions -- "For newly filled pools add 3 lbs of 10,000 gallons of water").
Nu-Clo directions state "this dosage provides approximately 35 ppm of cyanuric acid". However somehow my CYA level is reading 95-100 as measured by Pool company and verified by my own Taylor kit readings. I double checked both readings. But if I only added 12 lbs of CYA to new water how did my CYA get to 100?

Thanks for any insight.