so the water to the sump comes in from the top of the reactor???? I suppose it has a one way??/ I bought it used working from a big tank....Ill post pics of the co2 tank later...the bubble counter...also I calibrated the controller to match my ph monitor??? it has a calibration button on it and my ph monitor read 8.34 so I set the ph controller from 8.6 to 8.34????I hop this is right???? now how will the controller know when to shut the co2 bottle off? I understand the bo0ttle has a selenoid on it...but how does the selenoid know when to shut off????there is a line coming from the bubble reactor on the co2 bottle to the reactor)you said the small nipple on the bottom) the only other cord on the co2 bottle is a power cord for the selenoid????