For stocking, it fully depends on what age you get the fish. If they are young, around quarter to half dollar size, you could easily put up to 20 in a 180. Personally, I wouldnt. Full grown I would say 3-4 pairs would be perfect for that tank depending on how much plant growth you have. I would say if you go the young route, start out with 10-12 angels.
As far as the issue with the schoolers, I am not sure what is going on. I think if you have more loss though, you really need to consider taking them out. possibly getting a UV light if you dont have one hooked up to filtration may help with future issues, but I would probably dose the tank with a general antibiotic after removing some of your bioballs from your filters (they can last a few days (3) in tank water set aside) while you are dosing with antibiotic. After you dose, do a large water change again and replace bioballs
I have one I can put on.. It just kept malfunctioning last time and shocking the water (what the hell, I know). But an electrician nor the Pet Shop could find out why it was doing it, as it wasn't doing it when plugged in in town.. I might have thrown it, actually. Blah.
Yeah I was thinking 6 angels, maybe 8. The ones available to me are normally small...no bigger than an inch or so.
Just curious, why did AqAdvisor say they would grow out of the tank, when I put 6 in my list and took out the discus?