Which would make tank crash??

[ahiggins]

Have you thought about it being both?
Weakened/less than 100% coral critters but not necessarily showing it, got nuked because of a nutrient spike?
I can’t imagine stray voltage not having an impact on it but I’m not an expert on that by any means.

 

[CurtnStac]

Have you thought about it being both?
Weakened/less than 100% coral critters but not necessarily showing it, got nuked because of a nutrient spike?
I can’t imagine stray voltage not having an impact on it but I’m not an expert on that by any means.

I do think a nutrient spike did something. Maybe even a little ammonia might have spiked. Just can't see how things aren't getting better though. Maybe the damage is just done and there is no bouncing back from it, who knows!!
Stuff looked pretty dang good though literally right before this all went down. This is pic was just a week before...

 

[DLHDesign]

Grasping at straws here, but any change in flow or light?
I may have missed the answer; have you tested for ammonia?
You mentioned an APEX; do you have an ORP probe and has it shown any abnormal levels?

 

[CurtnStac]

Grasping at straws here, but any change in flow or light?
I may have missed the answer; have you tested for ammonia?
You mentioned an APEX; do you have an ORP probe and has it shown any abnormal levels?

No changes in anything and no orp probe. I did check for ammonia but with an api test. I probably should get a better one

 

[DLHDesign]

I was just reading up on aluminum levels in reef aquariums (link). While not conclusive, it's possible that having an elevated level led to a decline in the health of the tank inhabitants over time. Then when the nutrient spike happened, it was enough of a stressor that the corals (and potentially fish) had difficulties dealing with a change that would otherwise be more benign.

It doubt it will ever be possible to know for sure what happened to cause the issues you have had and are having. Focusing on the things that can be corrected should likely be the goal, and I think you've gotten a number of suggestions there from various members - several water changes over the course of a few days (and continuing until things are stable enough to reduce them), a grounding probe wouldn't be amiss, etc.

Good luck - keep us informed.