If you use a Stenner pump to add acid everyday, are you supposed to dilute the acid in the tank? And what ratio of dilution should you do? I seem to recall reading the instructions of the Rolachem saying you have to dilute acid. Thanks!

The Rola-Chem® Pro Series Pump Manual says that for chlorine one can use undiluted 15% chlorinating liquid but that the Norprene pump tubing (black) is included for 32% maximum hydrochloric acid feed. Under pump size requirements, they indicate you should dilute the acid 4:1 to 9:1 and that if you dilute by 9:1 that the acid pump may be the same size as the chlorine pump. It looks like for typical pool sizes they recommend a 12 gallon per day (GPD) pump, but that's because they assume higher commercial demands and periodic bursts rather than continuous flow.

I use a solaxx acid pump and mix 1 to 1

I've been diluting 3:1 without any problems over several years. Having some dilution is nice because it greatly cuts down on the fumes that can come out of the tank when you open it up.