Thanks Left C, no there was only one set of instructions, I also looked up MI's website & got their specifications for the SMS122 and I says the same thing as the enclosed instructions. I only have the 7.0 pH solution but went out and bought the 4.0 pH solution but when I inserted the electrode into it I could only set it to go to 5.8, 4.0 was not an option. Now, since I will be satisified with only using the 7.0 pH solution, my understanding is if I set the SETPOINT at 7.0, if it goes above 7.0 it will come on and start injection Co2 into the tank...question, at what pH point will it shut off? Is there a range? My problem is when I increase the setpoint above 7.0 nothing happens however when I decrease the setpoint to 5.8 it comes on and starts injecting Co2 into the aquarium. Please help me to see where I am going wrong & thanks for your time.
John.
