Supporting floor for 150g. Jack posts sufficient?

[SamMule]

I am going to be putting a 150g tank in my house. Will be a 5' 150g tank and a 34g sump.
Floor joists are 2x10 and span just shy of 15'. They are spaced 16" on center with x-bracing in-between. Tank will be running parallel to the joists and close to the center of the span and butted up against a non-load bearing wall.

The plan is to install 4 Jack posts in the crawlspace at each corner of the tank Similar to this:

I will obviously need something at the bottom to prevent them from settling into the ground like the one above. I may level the ground and screw them down to some 5' 2x10's to tie the bottoms together. Should help prevent any deflection or settling, right?

 

[danreef55]

I am not an engineer @RocketEngineer is. I think the columns should be supporting the joists not the subfloor.

 

[SamMule]

Yeah, I got to thinking about it and changed my mind. Going to run 6' beams or 4x4's perpendicular to the floor joists spaced about 5' apart centered over the 15' span. Starting from under the the wall and Going out towards the living room. This will help support the foot traffic from the entry way as well.
Basically right under here. Current tank is a 75g. New tank will be in the same spot

 

[danreef55]

Consider using two 2x8 boards glued and screwed together. or laminated lumber.

 

[SamMule]

Actually.... I have these from an old house project. That ought to do it!

 

[RocketEngineer]

Actually.... I have these from an old house project. That ought to do it!

Something like this should be strong enough to spread the load. And yeah, you want to be under the joists as these are taking the load, not the sub-floor.

 

[SamMule]

Thank you. Yeah, 6x8's. Should be able to get hangars for the bottom of the joists for that. Would like to do 12 or 14' length to help support the living room a little more if I can get them into the crawlspace.

 

[SamMule]

Ok, it's done. Floor is rock solid now!
6x8's 4 feet apart, spanning over 5 floor joists.