Great writeup Soulpatch. I entirely agree with you about the consistency of the dosing being the reason that growth seems much quicker, and I do think there is some untested/unverifyable value to the dissolution of coral absorbed elements besides calcium/alkalinity though its hard to say the impact it has.
Can't go wrong with spectrapure. There's a reason they're still sold, and still sold used in the hobby after being around for ~20 years.
On your coral colors, are you registering any nitrates and phosphates? I have to say, with my tank, being as crazy as I was about keeping nitrates and phosphates to 0, I was pretty disappointed with the coloration. As soon as I stopped dosing vodka and started feeding more (same food, PE Mysis, just feeding it more frequently), my coral color perked up within a week.
I couldn't starve out the bubble algae, so it keeps going again, and I have to manually remove it again, but it's actually growing no faster than it did with 0 nitrates or phosphates. Fortunately I'm not getting any other algae growth either.
Curious about your nutrient levels, and whether more food rather than less might help?