I’ve been routinely adding 6-8oz of acid daily to my 13,500 gal pool to keep the PH at 7.6. 3 days ago I converted from liquid Cl to a chlorine tablet feeder as I prepare to leave on vacation. Since the change the PH has dropped to 7.4 without the addition of any acid. My Cl level is 7.0, alkalinity 5.0, and CYA 60. Any reaso for the drop in PH?