A Good RO\DI unit would be #1, Water Movement #2
I have both the Vortech and the K's and if your not doing SPS then I would just stick to the MJ's on a ReadSea Wave Maker.
I had some issues with the LPS (Frog Spawn)could not handle the water movement of the Vortech on the other side of my 48x24x24 tank.
I would not waste my money on a Calc. reactor at this point, two part solution should serve you fine for LPS.