@nauticac4 - Husbandry has been pretty simple, really. In many ways no different than a smaller system. We do water changes every week on a single 1000-gallon system meaning each system gets a monthly water change. In the past, the systems got neglected in terms of water changes and there were periods where a system would not see a water change for 3 months. Over time, I believed this was the cause for our water chemistry to suffer. The Ca, Alk, and Mg are pretty low in the tanks, so that's what made me go out and buy calcium reactors for everything.
We do spot feed the corals regularly. Every other day we do the spot feeding and throw in a little food on the off days for the fish.
As far as fish go, I have a combo that I jokingly call the 'holy trinity.' It is the combination of a Ctenochaetus tang (Kole/Chevron/Tomini/Twinspot/etc.), Fox Face, and an Orange Spot Goby. The tang and fox face do a really great job of handling most types of algae whether it be the film type or the macroalgae variety. I don't think I will ever have a tank that doesn't include these two fish. The other thing I like about this combo is that the Ctenochaetus genus of tangs is one of the most docile. There is almost zero drama having both a fox face and tang in the same tank. In fact they tend to hang out together more than they are apart.
The Orange Spot Goby is the best sand sifter I've found. I have one in each of the six 125-gallon glass photography tanks. A single fish keeps the sand white and clean. Without the fish there, the sand would quickly turn brown (within 48 hours). The only problem I have with the gobies is that they tend to jump out a lot. We've put egg crate on the tank and the fish still manage to make it out.
The only fish we have that doesn't have a 'job' is a single tomato clown that lives in our bubble anemone tank.
@OceansParadise - If I was going to do something in ND, I would try a lean-to style greenhouse building rather than something like I've done. You really only need a south-facing lean-to design to gather the light and the walls on the north end can be insulated with residential materials. The more insulation you have the better off you will be. It certainly costs more up front, but I think you will quickly realize the importance of doing it right from the beginning.
They make polycarbonate sheets that are triple and quadruple layer specifically for places that have cold temperatures and pile snow on the structure. I would look into using a material like that. A 16mm triple wall polycarbonate sheet has an R-value of 2.5. If you used two of these with an air gap in the middle, you would get something close to an R-value of 7 which is really good.
