First set back

No I do not think so.

Honestly I have no clue what is going on with the fish.

Oxygen is like supply and demand to me. You have high O2 levels during the day that allow the flora and fauna to grow and become established. The system adjust it's population to what it can support. At night the system changes, even though the GPH is more than optimal, during the day it was supporting in proportion to the supply, cut back the supply at night but the demand remains the same.

Also if you are getting all your fish at one LFS or on-line perhaps try a different vendor.

You may never know, but I would only add one small to medium size cheaper fish, see how it does for a month and if all goes well proceed from there. I have a feeling the issue will resolve it's self.

 

Thanks Corailline.

To makes things evne more confusing, i found this:
Aquarium Grounding Probes

I've talked to electrical engineer at my work place, and he said that he does not know anything about fish, but he said that grounding aquarium will indeed create current where before was only potential. Current will exist between the source (submerged appliances) and the grounding probe. That path would be potentially harmful for something traveling through it.

....... now i wonder if i should take out the grounding probe ... lol ...

 

I think the whole voltage thing is a waste of time. Ill leave the grounding probe in the tank cause it's safer that way for humans.

Ordered Red Sea Oxygen test kit. Will wake up couple times during the night and measure at different times at night as well during the day. I've also ordered a phosphate test kit. Will give me something else to do

Electronic kits are just too expensive and seems like PITA to calibrate/use anyway.

Overall this whole odreal is definitely maknig me feel rather down about my new hobby