Rimless tanks overhang confusion

[Reefngeek]

I'm so confused why everyone says rimless tanks needs to be fully supported but then I see comments about Red Sea and Waterbox tanks being okay with overhang because they were designed that way. How is it they're designed to have the front overhang and why is it okay for their tanks to have the front panel not supported but it's not okay for other rimless tanks? Same question/idea regarding Fluval EVO. I know this is a much smaller tank but the bottom of the EVO has even less support. How is it okay for their tank to be like that but then anyone asking about (example) a 1/4 inch overhang on each side or front is asking for trouble? Can someone help clear this up for me? TIA

Edit: It looks like I posted this in the wrong forum. How do I move it?

 

[blaxsun]

Not sure how you move it - ask a mod? All I know is that on my Red Sea it has a steel plate to reinforce the front of the glass where it "floats", and that the gap down the aides is probably only 0.25".

 

[Reefngeek]

Not sure how you move it - ask a mod? All I know is that on my Red Sea it has a steel plate to reinforce the front of the glass where it "floats", and that the gap down the aides is probably only 0.25".

Thanks for that info. No where in all discussions I've found before have Red Sea owners said there's a steel plate reinforcement. If you don't mind me asking, how big is your tank? I may be paranoid but I have a small AquaTop 12 gallon long where the sides overhang by 3-4 mm. The sides looks like they are "floating". They're siliconed to the edge of the bottom glass. The bottom is fully supported on the stand. I'm thinking that this is okay but as I mentioned, I've looked through the web and all I see are discussions where everyone doesn't recommend any overhang but then others saying their Red Sea Reefers and Waterboxes are okay to overhang.

 

[blaxsun]

I have the Red Sea 750XXL, so I'm not sure which tanks all have the metal lip - assuming 625 and larger (but with the new G2 models there may be more). Mine also has corner reinforcements as well.

 

[Cell]

I thought on rimless tanks, the weight gets distributed evenly across the bottom so an inch overhang doesn't put added pressure on that spot, but more pressure on the rest of the surface that does make contact. There's a difference when the sides are sitting on top of the bottom pane vs attached to the ends, but I'm not sure how big of a difference it is. I thought more pressure is pushing outward on the sides of a tank, not downward, but not really sure.

@Joe Glass Cages will definitely know the right answer here!

 

[Reefngeek]

I thought on rimless tanks, the weight gets distributed evenly across the bottom so an inch overhang doesn't put added pressure on that spot, but more pressure on the rest of the surface that does make contact. There's a difference when the sides are sitting on top of the bottom pane vs attached to the ends, but I'm not sure how big of a difference it is. I thought more pressure is pushing outward on the sides of a tank, not downward, but not really sure.

@Joe Glass Cages will definitely know the right answer here!

That's what I thought as well regarding the pressure pushing outward. I honestly don't know why I only buy rimless tanks. I swear the anxiety of constantly thinking there's going to be a blow out is taking away the enjoyment. LOL

 

[Reefngeek]

I have the Red Sea 750XXL, so I'm not sure which tanks all have the metal lip - assuming 625 and larger (but with the new G2 models there may be more). Mine also has corner reinforcements as well.

This is fantastic to know. I've stayed away from Red Sea because the overhang on such big tanks scared me. I'll have to talk to my LFS guy about a possible order.

 

[Forty-Two]

My Neptunian Cube also has an overhang - not sure how much exactly - but the stand is also quite sturdy so I’m not concerned about it

 

[Pntbll687]

This is going to be a complete guess, but...

I bet the tanks that have the "overhang" is actually just the vertical panel, and the bottom panel is fully supported. Having the vertical panel supported really won't help anything, as almost all the pressure on that panel is horizontal, and the only downward pressure it feels is it's own weight from gravity.

 

[Cell]

This is going to be a complete guess, but...

I bet the tanks that have the "overhang" is actually just the vertical panel, and the bottom panel is fully supported. Having the vertical panel supported really won't help anything, as almost all the pressure on that panel is horizontal, and the only downward pressure it feels is it's own weight from gravity.

It's typically a bit more overhang than just the front panel to clear the thickness of the stand doors.

 

[exnisstech]

What Pntbll687 said is probably correct. This is the front edge of my redsea reefer 170. For sure different than any of my rimmed tanks where all 4 side panels sit on the bottom panel, and at least it looks like they do.

 

[Pntbll687]

What Pntbll687 said is probably correct. This is the front edge of my redsea reefer 170. For sure different than any of my rimmed tanks where all 4 side panels sit on the bottom panel, and at least it looks like they do.

Most rimmed tanks do not sit on the bottom panel at all. The bottom panel is usually recessed up about 1/2" and only contacts the bracing. This is why you don't need any support in the middle on rimmed tanks, just on the edges. Just go to anywhere that sells aqueon or marineland tanks and look at the stands, they are all open on the top with minimal cross brace.

 

[exnisstech]

I stand corrected. Then they are assembled like the rimless tanks with bottom panel inside the side panels. So I guess like the OP I don't understand why the redsea tanks don't need support on all corners

 

[waterbox15aio]

It depends. If the front pane of glass is outboard of the bottom pane, you really don’t need to support below the front pane as the water is pushing outwards horizontally on the side glass and only vertically on the bottom pane. If you switch the tanks glass configuration so the bottom glass is below all side panes, you just have to size the thickness of the bottom pane sufficiently that it is stiff enough to overhang without deflecting to some limit.

So plausible yes, how well builders understand and implement these concepts idk?

But in the end, just listen to the manufacturer if they have stricter requirements they want you to follow.

 

[waterbox15aio]

I stand corrected. Then they are assembled like the rimless tanks with bottom panel inside the side panels. So I guess like the OP I don't understand why the redsea tanks don't need support on all corners

Water pushes outwards horizontally on the vertical panes and only downwards on the bottom pane. There shouldn’t be any vertical force at underside of the vertical panes except due to the bottom panes pulling on the vertical panes via the silicone, and self weight. Regarding the bottom panel cantilevering, its only a problem if not sized with sufficient thickness.

 

[Pntbll687]

Water pushes outwards horizontally on the vertical panes and only downwards on the bottom pane. There shouldn’t be any vertical force at underside of the vertical panes except due to the bottom panes pulling on the vertical panes via the silicone.

This^^

And the minimal overhang doesn't have enough pressure to break the glass.

 

[blaxsun]

What Pntbll687 said is probably correct. This is the front edge of my redsea reefer 170. For sure different than any of my rimmed tanks where all 4 side panels sit on the bottom panel, and at least it looks like they do.

Mine is like this except instead of being able to see the glass there's a thin steel lip that extends out from the stand right up to the edge of the glass. So when you look up (as in this image) you still see the overhang - just that it's covered by black metal.

 

[EeyoreIsMySpiritAnimal]

@Miami Reef

 

[exnisstech]

Mine is like this except instead of being able to see the glass there's a thin steel lip that extends out from the stand right up to the edge of the glass. So when you look up (as in this image) you still see the overhang - just that it's covered by black metal.

Hmm. Maybe something they started doing or used to do and quit. I purchased mine Feb 2019 but not sure of the build date. Would probably make me nervous on a large tank but no so much on the 170.

 

[blaxsun]

Hmm. Maybe something they started doing or used to do and quit. I purchased mine Feb 2019 but not sure of the build date. Would probably make me nervous on a large tank but no so much on the 170.

I think it's only on the larger (625 and up) tanks, although with the G2 redesigns they may have extended this to other cabinet stands.