I would also suggest the DIY forum, but I will say it is pretty easy to do. I have done it a couple of times. Take out all media, just fill with CaCO3, make a little manifold with 5 total fittings, 2 for the inlet and outlet, then three smaller ones for water in, effluent, and co2 in. connect, inlet and outlet to this manifold. On the fitting closest to the outlet of the canister, will be your effluent out port, middle is water in, closest to inlet, is CO2 in (the closer to the actual inlet of the canister filter the better)
If you want to put in a pH probe port, you can make one out of PVC and put in in your manifold.
The efficiency of the reactor is not normally the best, just because it is easy to get CO2 bubbles built up inside the reactor, but they do work and are very inexpensive if you have the canister already.
