The evaporation issue is a good comment, but easily surmountable with an automatic top-off system. Since the sump will be smaller than the display, it probably wouldn't need more than an inch or so of air space to allow for power outages.
Maybe I'll split the difference and leave the sump in...
Thanks for the responses - The attic spaces are adjacent to living spaces on the second floor, so access is no problem. It sounds like this is doable, although we may need to build a fish tank room in the attic space and have the space ducted for heating & cooling. I'll post the question on a...
The average attic in South MS gets to unbearably hot - but with this type of construction, the insulation is on the underside of the roofing. So the attic is inside the heated/cooled envelope.
The house hasn't been started yet, so a waterline & drain would be easy to design in.
I am working on house plans (hoping to start rebuilding within two months) and while trying to figure out how to keep tank humidity & salt from being a problem, it occured to me that we have tons of space in the attic for a fish tank room.
The house will be ICF with sprayed insulation under...
