From my understanding and experience, it takes a while for CYA to show well on the test. Usually a day or two depending on how good your circulation is. You are running the pump right? If you used pool math to calculate how much to add to get it to 30, then you should be good unless your CYA was not potent, which I have encountered with brands from Walmart. Pool store CYA has been better but the best I’ve had is Puritech brand from Amazon. It is powder and is less expensive than any local brands and works like a charm. It’s too late for you to order and use now but for future reference.