Is there tile directly under the tank? If not, I still don't think you need to reinforce. A 7 year old house will be built to a standard that a fish tank with a mere 12-13" water depth is nothing to worry about especially with the perpendicular walls so close to the tank (as it appears in the diagram anyway). If there is tile right under the tank, then I think Steve's suggestion to run the support beam along the foundation wall is the best bet. You need to protect the wood from moisture though if it will be in contact with concrete.

What is the distance from the Foundation wall to LVL ?
And what is 'LVL' ?

One thing I see that would make me uncomfortable is it looks like you are asking the plywood sheeting to take the whole load.
If this is true, and the tank is not sitting directly on the joists, I'd recommend you sister those joists far enough under the tank so the plywood doesn't deflect and fail. Plus that would take out your tiles :biggrin:
There is a formula for sistering, but I can't find it on the web right now.

Yes. the tank will sit on tiles

Please see my new sketch because my memory served me wrong. The beam actually runs from one green post to another green post and it stops at the left green post.

The space that is underneath the tank is reserved for another big fowlr tank that I plan for future, so the sump will eventually move down to basement. Therefore i don't want any post underneath the tank


My new calculation is from wall to LVL is 17.3 feet. the tank will be 1.8 feet from the wall. And it will be 10 feet long so about 5.5 feet from the LVL

Hmm sistering joints which means i have to move current plumping and heat ducts that are currently between those joints.



Here is my latest sketch
http://www.canreef.com/vbulletin/pic...pictureid=4997

Was thinking of putting a LVL beem with two metal posts

Future for another tank that hook up with the upstairs tank

Ohhh...I think you're going to be in trouble without reinforcing the plywood since the tank is sitting in between the joists. Just a slight movement will pop those tiles off. Another option is to pull up the tiles that will be under the tank and install them with flexible thinset and sanded silicone grout.

What about putting two beams, either side of the tank from the foundation wall to the two green verticals. Either with your idea of using steel posts or drilling into foundation wall and installing hangers, the same to the green vertical posts.
Then you can install two or more beams right to left, between these beams with a hanger like the ones used here
http://www.ilevel.com/roofs/r_MicrollamLVL_beams.aspx
this way, you would not lose too much height in the basement
you would use 2x8 or 2x10s (more research needed here.

This would only hold up your existing floor joists. As mentioned already this would not support the plywood floor that the tank sits on.

can you make the stand for the tank wider then it needs to be?....... it would distribute the weight over a greater area and give you some piece of mind......but really.....135 g over 10' shouldnt be an issue.....especially if the house is new and assuming the framers did the floor properly:wink:

yeah id have to agree if you were hitting the joists with your tank you would be in a better position(depending on the type of tile/stone and if it was set right)

personally i would remove the tiles all together where the tank sits and double up the plywood with 1/4" ply to fill the void or do as doug said and build the stand so its a little bigger than the tank and sits on the joist


edit****

I probably will do this. Thanks

I think i probably has to go this way instead of doing two more post. But then not sure how i am going to move the drain pipe that is currently sitting between 2 joints.




Thanks for everyone inputs so far, I learned lots of new stuff today

Could you draw the drain in there? Does it just run down between the two joists the tank is over top? Drains are pretty easy to move. Adding a handful of 2x4" supports perpendicular to the joists would be enough to let you sleep at night. Screw them to the floor and then screw through the joists into the supports. Like a ladder between the joists...know what I mean? I hope you do because I can't draw worth a crap in those drawing programs! :p