While buying some corals from another member here (thanks again btw), we discussed lower Alk levels being required in low nutrient systems. We briefly pondered the mechanism that causes burnt tips on SPS that so many are familiar with when Alk rises too high and nutrients are close to zero.
Anywho... I stumbled across this article at Advanced Aquarist where they measured the rate of photosynthesis and growth at various levels of Alkalinity. The cause of burnt tips is speculated at the very end. For those that like to nerd out, enjoy!
How to Grow Corals Quicker: Effects of Various Alkalinity Concentrations on Rates of Zooxanthellae Photosynthesis