Looking for advice on floor to support 120g tank

[Ming36]

I plan to install a reefer 425, weighing approximately 120g in total. My floor consists of traditional wood with joists (2X10), and the ideal position for display is parallel to the joists. However, I am concerned about whether the floor can adequately support the tank. After conducting some research, I am considering placing a 2ft 4X4 beam (in green) supported by two steel floor jack posts (in orange) on concrete pier block to reinforce the joists in 3.5ft crawl space, as illustrated below. I would appreciate some advice on whether this solution is reasonable or if it might be overkill.

 

[CO2TLEY]

Is it possible to just put it parallel to the joist but up against a load bearing wall?

 

[mike550]

@Ming36 Im not a structural expert but I like your approach. But why wouldn’t you put the 4x4 beam closer to the midpoint of the tank? So about 2’ from the beam?

I’d also look at how the joists are secured to the beam on the tank end.

 

[Asm481]

If your existing floor joists are on top of the beam, I would put your steel posts closer to the outside (left) in that picture. If your joists are hung by hangers, I would use two more steel posts near the wall. No faith in the hangers holding under our weight. Also I would bolt together two 2x6 for my beam rather then a 4x4. A 4x4 allows some sway.
Just looked at your drawing again....have your new beam extend to the next joist beyond the tank to keep it all tied together better.

 

[exnisstech]

your plan looks very similar to what I did for my 180 gallon. One end close to the beam and the added support close to the opposite end. In the next room a 150 gallon was in place almost the same as the 180 only on the opposite side of the beam and I used the same type of support. Both tanks were up for years and the 180 is still up and floor is fine. There was also a second 180 in the same room for years running next to the beam so two 180 and a 150 within 8ft of each other. I think some people underestimate how strong typical floor structures are. Your plan looks fine to me. Only difference is I made my beam out of 2x4s and a 2x6. The house center beam is just 3x10s with pole jacks every 10ft. Disclaimer. I fixed cars for a living an am not a structural engineer

 

[Ming36]

Thanks all for the great suggestions!

@Ming36 Im not a structural expert but I like your approach. But why wouldn’t you put the 4x4 beam closer to the midpoint of the tank? So about 2’ from the beam?

I’d also look at how the joists are secured to the beam on the tank end.

If your existing floor joists are on top of the beam, I would put your steel posts closer to the outside (left) in that picture. If your joists are hung by hangers, I would use two more steel posts near the wall. No faith in the hangers holding under our weight. Also I would bolt together two 2x6 for my beam rather then a 4x4. A 4x4 allows some sway.
Just looked at your drawing again....have your new beam extend to the next joist beyond the tank to keep it all tied together better.

Joists are put on top of the beam (4X10) of 1 inch, but looks not that sturdy

your plan looks very similar to what I did for my 180 gallon. One end close to the beam and the added support close to the opposite end. In the next room a 150 gallon was in place almost the same as the 180 only on the opposite side of the beam and I used the same type of support. Both tanks were up for years and the 180 is still up and floor is fine. There was also a second 180 in the same room for years running next to the beam so two 180 and a 150 within 8ft of each other. I think some people underestimate how strong typical floor structures are. Your plan looks fine to me. Only difference is I made my beam out of 2x4s and a 2x6. The house center beam is just 3x10s with pole jacks every 10ft. Disclaimer. I fixed cars for a living an am not a structural engineer

I like exnisstech's design, pretty nice and clean.
If I apply the same concept, it would resemble the following diagram, where one post supports three joists. However, considering that the tank is not positioned in the center, I'm concerned if this arrangement would still be acceptable.