The Ocean Acidification Facility is equipped to handle up to 9 replicate 50L treatment tanks for 4 different pH treatments and is easily modified to accommodate other designs. Carbonate chemistry is altered and then maintained by a stock solution of bubbled, high pCO2 seawater that is then dosed into header tanks for each treatment using a simple digitally-controlled interface. The flow-through system can be used at a range of temperatures and is well-suited for both short- and long-term pCO2 exposure experiments. A refrigerated shipping container with a similar setup allowing for triplicate tanks of four treatments allows for cold-water experiments (below 8°C).