I can't believe it has been almost a year since I've updated my thread... I've been pretty down about this zoanthid issue that I still have not been able to solve. I've pretty much just given up on figuring it out at this point. I added a pair of peppermint shrimp and they completely eradicated those little aiptasia like creatures. Haven't seen any of them since. The zoanthids still haven't recovered, so I'm standing by my original thought that they weren't the problem to begin with. The tank has seen better days, but I decided to put some effort back into it to try and reahab it after neglecting it for a while.
I decided after watching the BRS videos about the Kessil A360WE that is just isn't powerful enough for my tank. I like the sleek design of the Radion XR15W so I decided to make a change. Only thing I needed to worry about was mounting it. I have a mount I really like for the existing Kessil, so I wanted to reuse that if I could. I had some back and forth with Ecotech and they offered to sell me the part that I wanted to make it work.
Here's the typical bracket part of the RMS for the XR15. I really only want the "X-shaped" part of this, so I set about disassembling it.
Turns out it's really easy to pop the top of the bracket off with a pair of pliers. Here's what you're left with...
When I popped it off, I was really happy with what I saw. I just needed a couple of washers, a bolt and a nut and I had what I needed. There's nothing special about those parts, so I didn't take a pic

Here's the first test fit...
Pretty good! Here's the final assembled fixture.