100gal on mid level

[lastlight]

For me there is a big difference between the floor holding it and the floor holding it without bounce. You'll certainly have bounce with that volume if there is no additional support from underneath.

[kien]

Originally Posted by JDigital

^^ Did you have to add support for yours? I can't remember...

I did not. I decided that mine was close enough to a cross beam (whatever those are called; the beam that the joists sit on!), and the tank runs perpendicular to five or six 2x10 joists.

I did ask around, on forums (there are a few builders around here) and at LFSs and *everyone* said about 150g is the top end of what you can comfortably put on the main floor without worrying too much about extra support. That's why I ended up with a 150 rather than say, a 180 or 200+ like Bretts. Beyond that (150g) then you should consider it (extra support). For what that's worth.