Ever consider using acid to etch it? An overnight soak in vineager isn't long enough to do anything
ATI hybrid fixture, and yes I agree this hobby can be maddening sometimes but I guess it if was easy we would not have reef forums to commiserate in the fun. Soem corals responded very well to the LEDs and some did not, so we figured lets go with the best of both worlds and run the hybrid fixutre. It seems that going with both is becoming more popular as people want more even spread and better colors. With the dimmable fixtures, my electricity bill did not go nuts as I don't have to run the T5s at full power (they peak around 60) and the LEDs peak around 30 and I still have plenty of light. We even bleached some SPS at first and start all of our corals on the sand bed.
I agree with whom ever said the vinegar for one day wont be enough to etch the rock. I've ready that muratic acid is the way to go. It will bubble tons of crap off the rock. And to remove phosphate a lot of people run the pool grade stuff with great results. I think the vinegar will clean but do little for phosphates.
When I cured rocks I used Brightwell PhosphatE. I know it is not a long term solution but after two applications the rocks were no longer leaching PO4.
Are you doing regular water changes? When I had a phosphate issue I used kents phosphate sponge, it really works. http://www.marinedepot.com/Kent_Mar...ter_Media-Kent_Marine-KM9151-FIFMCHPR-vi.html
For what it's worth I have used vinegar a couple of time to etch some questionable rock I acquired. It is more then powerful enough to clean even the dirtiest of rock when used straight. And there is the added benefit of not worrying about a trip to the hospital if mishandled.