Milwaukee SMS-122 pH controller addition

Recently I updated my 75 Gallon Show tank with a calcium reactor from craigslist. While cheap, it didn’t come with all of the necesary items, including a solenoid, and a pH controller. The calcium reactor supplies the tank with much needed calcium and alkalinity by dissolving clacium reactor media at a lower pH level(usually between 6.5 and 6.7, depending on the media).

Lowering the pH is done by injecting carbon dioxide(CO2). In order to keep the pH steady and at a low level, a bubble counter is usually used to monitor the rate at which CO2 enters the calcium reactor, and then monitored with pH test kits. Adding a pH controller and a (normally-off)CO2 solenoid to this, simplifies the prodcedure  by controlling when the CO2 is allowed to enter the calcium reactor, determined by the pH of the water coming out of the calcium reactor(effluent). This is done via pH probe sitting in an effluent cup. I made mine out of a office style vertical pen holder, cutting holes with a dremel to allow for an effluent line to come in, and a drain out the bottom, allowing a pool of effluent water to be monitored by the pH probe from the Milwaukee SMS-122.

With the pH probe gathering the pH of the effluent water, the Milkwaukee SMS-122 pH controller monitors the pH, and when it rises above the set point, flips on the AC outlet pod attached to it. This is where the CO2 solenoid comes in. The operation of the solenoid is pretty simple. When power is applied to the AC plug, open the valve, when power isn’t supplied, close the valve. Easy enough. The solenoid is put in place between the needle valve connected to the CO2 pressure regulator(on the tank) and the bubble counter(which then goes to the reactor), allowing the flow to be set by the needle valve, and indicated by the bubble counter, when the solenoid is powered ON, and the solenoid valve is open. At this point, assuming the pH controller is already calibrated(mine came calibrated already, but I double checked it with the included fluids), and the set point set to what you would like, the pH will be held close to steady to wherever the set point is(in the case of a ca reactor, 6.5-6.7ish).

Having this setup, now the only thing to determine with the reactor is the flow rate of the effluent from the reactor, as well as to watch the pH of the tank, so that the lower pH water coming from the reactor doesn’t drop the pH of the tank too much, while increasing your calcium and alkalinity.

Tags: Ac Outlet, Ac Plug, alkalinity, calcium reactor, Carbon Dioxide, Co2 Pressure Regulator, Co2 Reactor, Co2 Regulator, Craigslist, Dremel, Effluent Water, Milwaukee Sms 122, Needle Valve, Pen Holder, pH controller, Ph Level, Ph Probe, Ph Test, Reef Tank, Saltater Tank, Saltwater, show tank, solenoid, Solenoid Valve, Test Kits