Update time. Been a lot of events.
So I wanted to try skimmer less but my pH got into the 8.7s! On 2 calibrated probes on both an apex and rkl. Added powerhead in sump but eventually put skimmer back in, however I pulled it out just now and will try few other options because with small sump it's hard to keep the skimmer free of gunk and a pain to take out for cleaning.
The corals didn't look so great after a while. The last thing I can think of is the epoxy for the rock (jb marine, not water weld) is giving problems.
So.... Set up 40b and 20l sump and moved all the coral there - lucky had all parts for a make shift setup.
Broke apart all the rock, bleach and acid treatment and a LOT of effort to peel, grind, chisel and drill epoxy out. It had turned yellow which could be leaching.
After that was done soak in ro/Di with triton detox and another compound unique corals sells to pull elements out (can't remember, it's something odd) then I used aquaforrest reef cement to make new structure.
That reef cement is good stuff. Needs bit of practice to not make a mess and a couple parts needed re-cement, but the overall structure is stronger and looks better than epoxy.
Put it back in the tank and after a while added coral back in.
Sure hope that's the issue. Never, ever, had such trouble with a tank, reef or not. It has been looking good for a few weeks now.
Also recently added some BTA, never had nems but they should go great with the rock. Added maxspect foam over the gyres.
Whew. That's a big update