In the case of waste water quality, there is a few different tests for phosphate, ortho vs total. They are used to test for different types of phosphates like biphosphates and triphosphate, and lots of other forms. So there are different types of phosphates, but I really don't know if they make a difference in the reef.

But all that said, your corals look great!

The funny thing is, I am currently using GFO to lower my phosphates and it is now at .15 instead of .25 and some of my corals are turning brown. This is wierd. They had better colors when my phosphates were higher or maybe this is just a coincidence and has another cause. Not all of them are turning brown but some are going lighter but more brown.

Could be a few things. But have read that you should not lower phosphates too quickly, as that can shock them. Although, I wouldn't have thought going from .25 to 15 would be too fast...

Currently my P04 is running between .08 and .13. Was down to zero earlier in the year, and trying to get it back down there again. SPS does not seem to be affected, though. But I did get some algae.

+1