An engineering and water pressure question

[Fishdude]

So if one were to drill two tanks at the sides and use bulkheads to connect them (like building a tunnel with water) would this change the water pressure on the glass panels of the tank? And would that lead to failure of the glass? I'm not an engineer so I'm really curious.

[ChemBob]

It would not change the water pressure. That is strictly a function of the depth of the water. However, it would add additional forces to the glass. The weight of the tube/tunnel will add stress to the glass. The weight could be mitigated a number of ways, and is likely not a huge concern given the number of tanks that are drilled on the back so long as you have a reasonably sized tunnel or support it independently. 

My bigger concern would be associated with any misalignment of the tube. This would create stresses/forces on the various components of the system, such as the glass, bulkhead, or pipe. This is the larger risk in my opinion, as the forces could be applied at odd angles. Rather than a pipe, a flexible connection such as a hose could be used. You'd need to verify the hose can withstand the water pressure at the depth you want the tunnel. I am pretty sure you can find easily find clear 1 inch hose for the water head of all the standard tanks, but I'm not sure about larger. 

I guess it is possible, but why? What is your goal? Fish swimming through it, or simply water transfer between the tanks?

[CT_]

What Chembob said. except I think if you got an acrylic tube and made it long enough (like a few times longer than it is wide) it would be compliant enough to not stress anything.  Especially if you put the tanks in place then glued the tube.  Also I bet if your hole isn't a perfect fit the gap filled by the silicone would be compliant enough too.  You could test wiggle room before gluing.

 

I say go for it if you want!  but maybe put it in the basement incase it all explodes 😛

 

 

[gardenman]

9 hours ago, ChemBob said:

It would not change the water pressure. That is strictly a function of the depth of the water. However, it would add additional forces to the glass. The weight of the tube/tunnel will add stress to the glass. The weight could be mitigated a number of ways, and is likely not a huge concern given the number of tanks that are drilled on the back so long as you have a reasonably sized tunnel or support it independently. 

My bigger concern would be associated with any misalignment of the tube. This would create stresses/forces on the various components of the system, such as the glass, bulkhead, or pipe. This is the larger risk in my opinion, as the forces could be applied at odd angles. Rather than a pipe, a flexible connection such as a hose could be used. You'd need to verify the hose can withstand the water pressure at the depth you want the tunnel. I am pretty sure you can find easily find clear 1 inch hose for the water head of all the standard tanks, but I'm not sure about larger. 

I guess it is possible, but why? What is your goal? Fish swimming through it, or simply water transfer between the tanks?

Interesting. I get what you're saying about the depth of the water controlling the water pressure, but you're also adding more water volume to the combined tanks. I keep having this picture of someone attaching a ten gallon, dollar-per-gallon Petsmart sale tank near the top of the six million gallon display tank at the Atlanta Aquarium and saying, "It'll be fine."  Technically the ten gallon tank is still just holding ten gallons, but that's a whole lot of water on the other side looking for a place to go. 

Back on topic, in a normal use situation (not six million gallons on the other side) I would think you'd be fine. 

[Fishdude]

My friend and I want to put together 2 50g lowboy tanks using these connections. Fish swim through and have a much bigger area along the bottom.