I see a lot of similarities out there. I'm using a Salifert PO4 kit, and the bulbs are different ages. The "centre" of the 3 is about 8 months, left has been running about 3 months and I just firied up the right bulb recently as I added more SPS to that side. It is possible that this outbreak was from firing up the 3rd bulb, but I would have thought it would have broken out earlier when I fired up the second bulb... who knows. The sea hare is already making some headroom, yaaa!!
I have a 70g with a stars and stripes puffer in it, he eats 4 large shrimp a day, i'm sure his, uh, crap, adds to the phosphates...