Milwaukee SMS122 pH controller

[fort384]

I have had my pH controller installed for about 10 days now... am wondering about optimal setup.

As of now, I have it set to shut off at 6.7. My question is, how sensitive is it supposed to be? It shuts off at 6.7, but doesn't turn back on until 6.9. Is this normal? With my KH, 6.8 pH should be ~35 ppm CO2. So, nearest I can figure with a pH shift from 6.7 to 6.9, I am getting a fluctuation in CO2 ppm from about 25-50, which seems ok. Just seems like the controller isn't dialing it in as much as I thought it could. I was expecting almost 0 pH shift. Is the unit working properly?

Also, as far as bps, I have it set right around 1 bps. This feeds my 5G nano tank (my drop checker in that tank indicates CO2 levels are ok), and the 29G tank. Is it better to turn it up so the CO2 adjusts quicker, or turn it down so it is more gradual? It seems to me, the amount of CO2 used should be about the same regardless of how many bps I set it to since it is turning off and on based on pH. Any thoughts?

 

[SparKy697]

That little difference between when the controller shuts off and when it turns on is often called dead band. What you see sounds very normal. If it were not for that little dead band, this thing would be turning on and off all the time. Think of your thermostat in your home. If you set it to 70, the furnace will run until the temp reaches 70, but it does not come right back on when the temp drops to 69.8. Be thankful for that

The fact that the controller is turning the co2 off and on would tend to make me think that you are set up nicely. If the bps were too slow, you might never see it turn off. If it were set too high, you might notice it only staying on for a short time compared to the off time.

IMO it sounds like you have a good setup going there.

 

[jrp1588]

mine does the same thing. I think you are fine