Be prepared to lay down some serious cash. First make sure you are going to really need one. Do you know what your load is and does it require one based on the levels you are dosing to keep up. I have a Korallin it's okay but I think it is hard to adjust. However, I think they all would be. I have had it since 1-06. Got a pH controller and the pH lid for it. It was about $800 (something) with everything. The kit was $611 for the 1502 but with the other items controller, aqualifter, lid. You can do a lot of dosing with Mrs. Wages pickling lime at $3.00 a jar before you get up to the cost of a CA reactor.