Had a beer with a construction buddy of mine and talked fish tanks (ba$tard made me pick up the tab :lol
. The new tank wil be more than adequately supported in the middle and one end, but I'm a bit worried about the other end. Joists are 9" deep (not 9 1/2", curious), so his counsel was to sister/scab the beams that run parallel to the one end with either LVL or doubled up 3/4" plywood. New joist is a 12' span that sits on sills on both ends. Plus I can slip a jack post in the middle of one that won't be a eyesore.
