I have greater calcium and alkalinity demands than I expected at this point, which are resulting in having to dose two-part to keep up... so I bit the bullet and ordered a calcium reactor package. I went with a GEO 6x24 model which should be more than enough for my system.
While I was loading up the cart, I also got enough bits and pieces to redo my T5 setup as 4x80 watt (5') lamps instead of 6x39 watt (3' lamps). The 3' bulbs turned out to be a fairly expensive mistake; the wiring made it harder to troubleshoot bad bulbs, the replacement cost for the bulbs was almost double, and there was just no clearance to get cooling fans in place with the canopy skins on. Lesson learned.