Thoughts on unnexplained (and very sad) die-off

[jostafew]

Not sure how to answer the microbubbles question. When the ATO resevoir would emptly (and I didn't notice) and the return chamber got to a certain point then yes the return pump would shoot micro bubbles into the system. I wouldn't call that an ongoing problem though. I beleive the loc-line return pipes did leach a little bit of air into the system and blow a very small amount of micro bubbles into the system too, but pretty minimal and no more than were present back when the system was stable.

Currently I do have a micro bubble problem on ver 2.0 of the system, but I have a few things yet to do to resolve that issue.

As for toxins, I don't think there was anything exotic in terms of livestock that would emit toxins while alive, but perhaps after death? There are a few zoa & paly colonies in the tank which we know are toxic if damaged, but no major trauma to those. On the list of inverts that died and decomposed in the tank include a large pincushion urchin, smaller tuxedo urchin, two small red starfish, brittle star, numerous snails and hermit crabs. There were only four fish listed in previous posts.

Dosing is pretty minimal; IO salt, BRS Kalk (not using anymore), occasional Seachem Calcium and Reef Builder Alk supplements. Was experimenting with dosing iron and Lugol's a while back, but it had been quite a while since the last dose of those.