Adding purple up IS dosing. He is waiting for a disaster if he isn't testing, as was already stated.
I use Reef Crystals and still have to add Calc, Alk and mag. I have acans, chalices, and sps corals. Dosing is sooo easy. I still have some C balance to use up, but have already used up my magnesium due to needing to add soo much to raise just 100 ppm (I think it's ppm anyway...lol). I bought Bulk Reef Supply's basic mixing kit and mixed my magnesium. I have to add 13oz!! just to raise it 100ppm in a 49g water volume.