I am using the Korallin 1502 reactor. It is a really good reactor, but I don't think you will need one if you don't have a lot of coral. Water changes are enough to replenish the minerals. I find it hard to adjust the bubles per minute and the drip rate, very touchy. I use an Aquacontroller Jr. to monitor the PH in the effluent cup and keep it at 6.5 to 6.8 PH. I monitor mine frequently because CO2 can build up in the reactor if your bubbles and drip rate are not set right.
I think the drip rate is also affected by calcium accumulation in the line.