Starting to regret buying a 180 and its not even set up yet

[TheAquarian]

That’s much stronger, block the entire length of the beam the mor joist you connect the more you distribute the loads, you only need to sister the joists under the tank and only up to the beam. So in this last sketch they would be 2’ in length.

 

[rck329]

The 40 psf (lbs per square foot) live and 10 psf dead are distributed loads. They don't really apply to point loads. Good reading here:

http://www.african-cichlid.com/Structure.htm