I can add his tank is as clean as any bare bottomed tank could be, with all the current & the siphon cleaning. So its not accumulated detritus causing problems, or if it was most all dsb type tanks would fail.
I have to wonder if Bev is correct on the test kits Mike. Even more so, with a nitrate test. If its at that level and/or you have phosphates, then all the algae, bananna trees & halide lighting over your honkin sump, is all for not?? Not to mention that huge skimmer??
But what can account for the darn turf algae. {scratches his head}. Maybe Doc Ron was right a few years ago, when he said the rock stores up the crap. I dunno. I once said when the time comes that I need to throw out my gazzillion bucks a lb. rock and buy new stuff, is the day I take up something else.
It seems strange to have to fight problems that normally plague newer aquarists & newer tanks, not someone with a seasoned tank and all that equipment cleaning it? Perhaps the bleaching that happened in a couple corals, could be attributed to where the colonies came from but that does not account for the frag bleaching AND all the rest doing fine.
Even if it was a bad pail of salt or something, still does not help us with the problem of the turf algae. It would be interesting to see a nitrate & phosphate measure done with very good tests kits. That would help show us if or how a sump with calerpa works or not.