Pife thank goodness you mentioned this is a 6 year old thread. I forgot to look as I was reading all of those sort of scary, uninformed posts..
My po4 is currently .2 (elos high resolution test kit) been there for a good 6 months
Here is my Jason Fox flame when I added it about 2 months ago:
And here it is today:
Nitrates: 30-40 and phosphates.18-.22 the whole time.
Now, I DO intend to lower them eventually but I am not in a hurry. I have to do it extremely slowly and would rather do it with bacteria than gfo. I have not used gfo in many months. I find it yoyos the levels and I think this is the most important aspect of nutrients- not necessarily the actual levels but their stability.
Bxbe888, .09 is really not a concern at all. Don't blame the colour of your corals in high po4 because I doubt that is the cause.. not knowing anything about your system, I couldn't say what is the cause, however..
Every time things change in a reef, the corals may brown out a bit. Stability is key. Maturity of the system is important as well.. proper lighting, parameters etc these all play a role.