He uses a sealed 55g Rubbermaid now. His 280 is completely covered, but cooled with end fans.
Not sure how much a 70,s surface area and a sump, will cut down on evaporation. Agreed the smaller sealed sump would work. However if the Euroreef is to be used, then it still needs a hole cut in it for the skimmer to stick out.
However, that may be a better option than an open back with power filters.
I figure that will be about the same evaporation. I also wonder if the open back will alleviate the need for cooling fans, for vho lighting and if it will be less evaporation that way.
Whatcha think Mike.