The problem with just adding nitrate through feeding is that you actually add phosphate, which isn't removed by your anaerobic bacterias, and is removed at a much slower rate through your macros. So, the PO4 builds at a faster rate than the nitrate. It just depends on how you want to address the increasing PO4. It will de reduced through water changes, but because water changes also remove the nitrate, the PO4 continues to elevate.
I have gorgeous SPS! I'm into pinks and purples now, but I have the sexiest turquoise hydnopora on this planet! it grows like a weed! And, weird as it sounds, I dose nitrogen compounds!
I run without a skimmer, with a ton of sponge and a lot of macros, seagrass and mangroves, in my main display and a large sump. I really think once your tank hits zero nitrate, you might consider the crazy talk! Phosphate in my system was much more problematic when I just addressed the nitrate issue.
But, it is a pretty new concept with SPS fans. I do think the crazy talkers are going to win them over, though!
But, if it is too weird, I am going to invent a PO4 reactor! Think it could be a big seller before everyone figures it out!