How much weight will a 4x6 hold?

New plan! So, I'm changing my plans a little and want to know how much weight will a 4x6 support?

I'll have 4 4x6's sitting side by side, 4" high and 6" wide. They are 8' long. The tank will sit centered on them and is 6' long. It's going to be sitting on 3 rows of cinder blocks. The blocks will cover the full width and will be centered and spaced 5' apart.

Finally, the 4x6's are untreated Douglas Fir.

Stock list for the tank:

4 pacus

2 silver arowana

4 rtc's

2 motoros

That should get people's attention. I'm not stocking the tank with those fish. That would clearly be a disaster as it's only a 150 gallon tank. I just need someone to help me determine if the 4x6's will support my 150g tank.

dogofwar said:

Four 4"x6"s will hold a 150g and then some. I'd just put a piece of styro over the top of it to iron out any imperfections.

Why not just do 3 stacks of cinder blocks (sides and middle) and use 2x4s (or plywood for that matter)?

Matt

Click to expand...

This set-up is a temporary home for my motoro until I build my monster tank. To keep the water volume high, because of the high bio-load of a ray, I'm using a 75gal tank underneath for a sump/refugium. The 150g is 6' long and the 75g is 4' long. They're both the same width, so there wouldn't be room for center braces if I use the 75 for my sump.