I've made it clear the area directly around the tank is NOT to be cleaned at all (I'll do that). The biggest problem is that our cleaning crew is Ukrainian. Not a problem normally, but the language barrier is troublesome.
The bigger issue is that I've seen how they use the spray cleanser for our whiteboards... VERY liberally applied from about 8-12 inches from the board and then wiped down. Its quick, but a LOT more is used than is necessarily, which is where our issue comes in. Also, the fish tend to be just fine after initial placement in the tank, but after around 5pm-7pm, the "rapid breathing" begins - which again indicates it has to do with their ability to uptake oxygen from the water. The cories being unaffected is baffling, but they are so very different biologically, being air gulpers at times, and spending most of the time on the bottom, that the airborne stuff may not stay in the water long enough or circulate down to where they are as much... Guppies spend time everywhere, so if they survive, we'll have something to work with.
We are probably going to have to completely reconsider the bloodfins though. I don't know that I want to add any more for quite some time.
This is the most frustrated I've EVER been keeping fish. And this includes as a kid all the fish in the house dying while my parents went away and I stayed with my grandparents (2 blocks away) and cared for the fish. The house overheated the fish and they all died - every single one. It was the closest thing to the sight of 24 dead or dying bloodfins in this tank. At least in that case I knew the problem, but it was too late. In this case the unknown is the most upsetting part.