Tank crashing...could it be due to these?

[Aquattro]

Originally Posted by Son Of Skyline

Interesting. I've never thought about PO4 and how it might be affecting my system. I guess it wouldn't hurt to try a sponge. What's doxycycline?

Mason, doxycycline is an antibiotic prescribed for vibrio infections. Julian Sprung first announced it for treating elegance corals, and I researched it a lot before dosing. It isn't something I would recommend as a first (or second) course of action. I found that if I scratched my arm while working in my tank, I would get a large blistered infection at the site of skin breakage. This led me to believe that I might have an excess of vibrio bacteria in my tank. With the chain of events (DSB removal, high temps, excess SPS mucous), this was feasible for me. After treating, I did still experience some tissue loss. I have also worked at keeping my temp below 80, as this inhibits vibrio activity (so I've read).
I have also had a outbreak of algae in my (attached) frag tank, leading me to believe nutrients are at least partially to blame. NO3 is not detectable, and never has been. PO4 is the same, but not all PO4 is detectable. I believe this is the nutrient in question. And before anyone asks for proof, all I have is "guessing".
I've become very frustrated with all of this, and it's been going on for some time. I'm open to any suggestions at this point, although it looks like I haven't lost any tissue for about 5 days. And to reiterate, it is only acropora sp. SPS that are having this problem.