I acquired a 150 and a 125 used a number of years back, I built stands for both in place. I used mostly 2x4s but also some 2x6s. I basically sketched out a design, rented a compound miter saw and bought the lumber. My plan was to have the top os the two tanks at the same level, but I messed up one measurement and the fastest fix was to make the stand for the 125 a tad shorter than planned. I never "finished" either stand and to this day they are frame stands.
The bottoms are 2x4s flat with plywood on top. What you cannot see is there are 3 2x4 braces between the top frame rails. There is one in the dead center and the and additional one on either side. These give the stand extra bracing and help to keep the 2x4s straight. The biggest challenge is that lumber these days is rarely square. I had to use ratchet come-alongs to get things in place.
https://www.homedepot.com/p/Husky-1...n-Straps-with-S-Hook-2-Pack-FH0935E/312994484
Here are pics - I painted the wood with a semi-gloss exterior paint. It ehlps waterproof.
150 going onto the stand- the cross pies are visible
The 125
Here are both
Note the 4 corners use a 2x6 on the front and back but there is also a 2x4 L ed to the 2x6 at the 4 enduupports. The tanks sits on the 2x4s on end and I have a strip of foam weather stripping attached to the 2x4 such that the bottom frame of the tank sits atop the foam/ The 2x4s are not smoot on end and the faom acts to level out things when the weight of the tank compresses the foam.
While I had help from the two big gents getting the tanks in and on the stands, I did all of the stand contruction on my own. I do not use nails, I uses wood screws only.
These stands went up in 2012 bit were not put into use immediately. The 150 has been in used now for about 7 years and the 125 more like 5. The space under both is occupied. The 125 has a 45 long under it and the 150 has a canister plus a lot of supplies, That is one reason I never gave things a finished look. The tanks are sturdy enough to holw more weight than I have on them by a lot.
