Floor support.

[laga77]

I made a living installing footing and foundations for 30 years. This is my assessment and you can decide what you want to do. The dirt has been there for 95 years and is compacted as it is ever going to be. It is inside, not exposed to the elements, and is not going to move. Your tank is going to max out no more than 1000 pounds. That is not a lot but if you feel the floor needs some help then do it. We are not there and cannot make that call. Concrete blocks will work for you if you set them on flat, smooth ground. Then, place some pressure treated lumber across the top of the blocks and set your post on them. You do not need adjustable jacks. Cut the posts and fit as tight as possible. Shim with composite shims if necessary. Once the weight of the tank is on the floor nothing will move. Good Luck

 

[woodnaquanut]

Good pics! Much better than tiny pics!!

The way the joists are notched, right now they are functionally like a 2x4 (or worst). Adding the joist hangers will bring them back to full 2x6 strength. Make sure you put joist hangers on both ends of those joists.

The post looks suspicious. Check the bottom to make sure it's not rotted. Poking with a nail at the base will tell you what you need to know.

How far do the joists span? With the HVAC ducts there it will be difficult to add an additional beam.

 

[intyme]

Great thank you, the joist are at 16"ish on center. The support seems like it's just water stained. I think it's still in good shape. I thought of adding 2 4x4 posts with a cross member so over time it won't sag. The more I look at it, the easier my task will be. Thanks again for the piece of mind!

 

[davocean]

W/ just a little vertical support those beams should carry a pretty good load.
I'd grab a couple of the cement piers that have the bracket imbeded(like $8 at any hd)
and I'd do pressure treated 4x4 for vertical support.
Pressure treated anytime we do earth to wood or concrete to wood contact.
In a perfect world piers sit in a bed of concrete, but your soil may be compact enough and you probably can't do that easy.
Some might say this is overkill for that size tank, and it might be from what we can see from here, and while I'm sure that will hold the load mainly we just don't want any sagging down the road.

 

[intyme]

Some might say this is overkill for that size tank, and it might be from what we can see from here, and while I'm sure that will hold the load mainly we just don't want any sagging down the road.

You're probably right on the overkill thing. But.... I definitely don't want any floor sag over the next 10 years. Maybe by then I'll have a 180

 

[davocean]

W/ proper vertical supports added I see no reason why not.