It looks to me like it was a reef tank.
egg-crate, to hold stuff up off the bottom for water circulation.
probably just sitting their, and removable.
The Sump, looks like its just a 20g aquarium/DIY sump. IE glass/plexi-glass dividers siliconed in, etc.
Probably not all that big/great of a deal, unless thats the exact tank your looking for. And want it now.