Woah! Full stop! Without reading back through, I could have sworn at some point you stated that you had left out some vertical supports in one of your previous drawings; I assumed you meant a couple of supports for the top level, placed between the tanks on the middle level.
Are you seriously planning on building a 12 foot span out of unsupported 2x4's, on which you plan to slap three 60-gallon tanks? Wow. And I don't even know what to say about "sagulator"...
You are calculating everything to the last hairbreadth and fraction of an ounce, so let's mention that the load on the top shelf will be more than you think. I assume that 1440 was achieved by multiplying 3 x 60 x 8 pounds? This ignores the weight of substrate, rocks, or anything other than water within those tanks, not to mention the weight of the tanks themselves. I'd bet that will be at least a couple hundred extra pounds...probably not a dealbreaker, but if you are going to be precise...then be precise.
I'm also a bit leery of the "salgulator" when it questions the nature of the load: uniform or centre. If you had one long 180gallon tank on top, that would certainly be a uniform load. But do three separate 60gallon tanks qualify as one? I don't know; I do know that this whole thing makes me uncomfortable, and it's not even going into my house!
So let's say you build that unsupported 12 foot span, stick those tanks up top, and then fill only the centre one. Frankly, I wouldn't even do that, but just for gits'n'shiggles why don't you plug in a centre load of, say, 550 pounds (very likely for a single filled 60) and see what the ol' sagulator tells you. How much sag will occur? Will it be enough for the top edges of the tanks begin making contact with each other? How much lateral pressure might they apply to each other if they do?
Incidentally, my suggestion that you attach this structure to the wall was NOT intended to reinforce it in any way, but merely to stabilize the entire hopefully-rigid thing against tipping. Depending upon how well it is attached and how good the wall structure itself is, doing so might very well add rigidity to the rear horizontal support, but won't do anything for the front. If that occurs, then the front might sag while the rear does not, and now you have the center top tank leaning forwards more or less uniformly, while the two end tanks are not supported at all in the front inside corners.
I don't mean to sound negative; you asked for opinions, so I am expressing mine: You definitely should have vertical supports between the middle tanks, holding up the top level. You definitely should have some diagonal, both at the ends and on the backside, to increase rigidity.
And...it sounds as though this thing is being built so tight that all these tanks will barely be able to slide into it, with no gaps at all? What happens a few years down the road, when one of them develops a leak or breaks a glass panel, or for any other reason requires replacement...and you find that the tanks available to you then are a quarter-inch longer, or wider, or whatever? I really think you need to build in some "jiggle room" to allow for unforeseen surprises like that.
Edited to add: Okay, add
Milingu
to the (long) list of people who are more concise and type faster than I do...
Are you seriously planning on building a 12 foot span out of unsupported 2x4's, on which you plan to slap three 60-gallon tanks? Wow. And I don't even know what to say about "sagulator"...
You are calculating everything to the last hairbreadth and fraction of an ounce, so let's mention that the load on the top shelf will be more than you think. I assume that 1440 was achieved by multiplying 3 x 60 x 8 pounds? This ignores the weight of substrate, rocks, or anything other than water within those tanks, not to mention the weight of the tanks themselves. I'd bet that will be at least a couple hundred extra pounds...probably not a dealbreaker, but if you are going to be precise...then be precise.
I'm also a bit leery of the "salgulator" when it questions the nature of the load: uniform or centre. If you had one long 180gallon tank on top, that would certainly be a uniform load. But do three separate 60gallon tanks qualify as one? I don't know; I do know that this whole thing makes me uncomfortable, and it's not even going into my house!
So let's say you build that unsupported 12 foot span, stick those tanks up top, and then fill only the centre one. Frankly, I wouldn't even do that, but just for gits'n'shiggles why don't you plug in a centre load of, say, 550 pounds (very likely for a single filled 60) and see what the ol' sagulator tells you. How much sag will occur? Will it be enough for the top edges of the tanks begin making contact with each other? How much lateral pressure might they apply to each other if they do?
Incidentally, my suggestion that you attach this structure to the wall was NOT intended to reinforce it in any way, but merely to stabilize the entire hopefully-rigid thing against tipping. Depending upon how well it is attached and how good the wall structure itself is, doing so might very well add rigidity to the rear horizontal support, but won't do anything for the front. If that occurs, then the front might sag while the rear does not, and now you have the center top tank leaning forwards more or less uniformly, while the two end tanks are not supported at all in the front inside corners.
I don't mean to sound negative; you asked for opinions, so I am expressing mine: You definitely should have vertical supports between the middle tanks, holding up the top level. You definitely should have some diagonal, both at the ends and on the backside, to increase rigidity.
And...it sounds as though this thing is being built so tight that all these tanks will barely be able to slide into it, with no gaps at all? What happens a few years down the road, when one of them develops a leak or breaks a glass panel, or for any other reason requires replacement...and you find that the tanks available to you then are a quarter-inch longer, or wider, or whatever? I really think you need to build in some "jiggle room" to allow for unforeseen surprises like that.
Edited to add: Okay, add

