Ross, just curious. Do you have a skimmer ? My thought is it isn't the cause of the losses you've incurred anyway.
However, a suggestion that
perhaps it is an O2 defeciency is a valid one and deserves consideration. We all know no systems ever function or react in the same way. Hell, I've only got two tanks on a "full time" basis and both tanks undergo changes and catastrophies separately. Both tanks are set up virtually identical, obviously with the same water source etc. but there are too many variables to determine what works and what doesn't. Sure there is basic chemistry, biology, physics and all that mind boggling "mumbo-jumbo" that's always changing. It's those damn variables I mentioned previously that make input/recomendations from people, all over, so valuable a tool in solving a problem. I'm not directing this "lecture" to you Ross, nor anyone for that matter...this just seems to be "snowballing" and things are goona' be said that might be better left as thoughts...
I was thinking last night Ross of your situation and something came to mind...it's a long shot like the O2 concern... you made some DIY live rock ? Can something be "leaching" still from that ? I've read very little on the whole concept. It is unfamiliar to me but...? How are the inverts. doing ?
Finally, life is good...
Oooops. I see ya' mentioned you are skimming.