Protein Skimmer Power Bar Failure Death Toll....

[Aquattro]

Kien, I can't really disagree with you, as it does seem that obviously that was the deciding factor. I can't tell why, but the skimmer appears to have been the "last straw", indicating some other factor in play. My point, I guess, was that it "shouldn't" have been the skimmer, as lots of skimmerless tanks don't have powerheads pointing at the surface, or other forms of noticeable surface agitation. Maybe a too heavily stocked tank, high CO2 content in the room, etc. Lots of factors could have contributed, with the skimmer being the buffer. No skimmer, tank crossed the boundary into this situation.
It's always tough to diagnose something like this online. I'll revise my comment to be " while it's obvious the skimmer was the major contributor, it shouldn't have been", meaning I think there was a secondary cause.

[kien]

Being in Yellowknife your house must be fairly sealed up for a good portion of the year. Curious, what form of ventilation do you have? This is yet another variable that is different from some other people. Not too many reefers in Yellowknife I dont think. There is typically a major in house CO2 spike during the winter months especially for cold weather climates. The skimmer could have been keeping O2 and CO2 in the tank in a fragile balance, but once it was gone, the scale tipped in the wrong direction.

Sure, a lot of people can get away with not using a skimmer or not having to point their powerheads at the surface, but those same people may not have the same environmental challenges that your tank might be faced with being in Yellowknife. Again, there are so many variables from one tank to the other that you can't always say, "hey, well, Fred over there has the exact same tank as me and he doesn't use a skimmer, so I'll be perfectly fine without one too". "And hey, Joe over there doesn't point his power heads at the water surface, so why should I??" We all know the hobby doesn't work that way. It may very well be that your tank needs more aggressive oxygenation and gas exhaust than other tanks.

[ensquire]

Originally Posted by kien

Being in Yellowknife your house must be fairly sealed up for a good portion of the year. Curious, what form of ventilation do you have? This is yet another variable that is different from some other people. Not too many reefers in Yellowknife I dont think. There is typically a major in house CO2 spike during the winter months especially for cold weather climates. The skimmer could have been keeping O2 and CO2 in the tank in a fragile balance, but once it was gone, the scale tipped in the wrong direction.

Sure, a lot of people can get away with not using a skimmer or not having to point their powerheads at the surface, but those same people may not have the same environmental challenges that your tank might be faced with being in Yellowknife. Again, there are so many variables from one tank to the other that you can't always say, "hey, well, Fred over there has the exact same tank as me and he doesn't use a skimmer, so I'll be perfectly fine without one too". "And hey, Joe over there doesn't point his power heads at the water surface, so why should I??" We all know the hobby doesn't work that way. It may very well be that your tank needs more aggressive oxygenation and gas exhaust than other tanks.

Houses here are sealed up tightly yes. And in this older home we have a very passive exchange system. Just a couple of vents in washrooms and kitchen.
I have to get my test kit back from work and retest everything again to verify things. But everything left in the tank is healthy, happy, & hungry again today.
I agree with the idea that the skimmer shutting down for 12 hrs shouldnt have killed 7 previously healthy inhabitants, and until I confirm parameters I (we ) just don't get it .
I will change angle of powerheads if everyone thinks that that could be a problem, but the fluval return does point at the surface and agitates quite well. Maybe the fluval needs to be taken out of the equation , maybe it is a nutrient trap?

Final Tally
2 Pink Clowns
Bi color Blennie
Flame Angel
2 cleaner Shrimp
Coral Banded Shrimp

[daniella3d]

+1, That's what I meant as well. Not that it did not cause the death of fish, but rather it shouldn't have caused the death of all these fishes.

There is some real problems with that tank that must be addressed before this happen again, skimmer or no skimmer.

Originally Posted by Aquattro

My point, I guess, was that it "shouldn't" have been the skimmer, as lots of skimmerless tanks don't have powerheads pointing at the surface, or other forms of noticeable surface agitation.

[kien]

Hindsight is 20/20. It is easy enough to say now that the skimmer going titz up should not have killed your fish, but how could one have predicted that before hand? Like so many people here suggested, their tanks are fine
without a skimmer or powerheads pointing at the surface so yours should be fine too. Well, what happend when the skimmer went offline? How could you possibly account for all possible scenarios that are affecting your thank, many of which are intangible.

No doubt this hobby is tricky like that. It is difficult for anyone to predict these sorts of things. Running BioPellets shouldn't nuke my tank, but can it? Will it? Running ZeoVit shouldn't nuke my tank, but can it? Will it? This heater shouldn't die, but can it? Will it? Turning my skimmer off shouldn't nuke my tank, but can it? Will it?

[golf nut]

Originally Posted by Aquattro

I can't tell why, but the skimmer appears to have been the "last straw", indicating some other factor in play.

I agree, there is something else happening.