800g Tank Reseal (for the 2nd time)!

[Trouser Cough]

You keep going back to the weight of the water on the bottom panel. It's not about that, it's about the FORCE on the SIDE PANELS of the aquarium.

Explained better than I can, bullet point 4:

Physics of the fish tank

Welcome to my article on physics of the fish tank. I should start out saying that you could easily keep fish with out actually knowing any of this. It is however, in my opinion, interesting and of some value in understanding some of the aspects of aquaria. I have included some examples for...

www.aquariacentral.com

Wouldn't it be about both? I'd estimate pressure forces on the front and rear panels to be in the neighborhood of approx 2000# but I'd estimate the weight of the water (only) on the bottom pane to be approx 6000#. It is the deflection of the bottom pane that (may have) resulted in the compromised seal and likely not the other way around, no?

 

[Backfromthedead]

Wouldn't it be about both? I'd estimate pressure forces on the front and rear panels to be in the neighborhood of approx 2000# but I'd estimate the weight of the water (only) on the bottom pane to be approx 6000#. It is the deflection of the bottom pane that (may have) resulted in the compromised seal and likely not the other way around, no?

Yes both but the integrity of the structural silicone seam was compromised by the hydrostatic force pushing the side panel out over time. It's not like the water pressure shattered the bottom panel and as you've pointed out it's plenty strong enough to hold the water. The silicone was stretched OUT and then the bottom panel will do what anything does with gravity cause there's nothing holding it up anymore. I've been dancing around saying this cause I don't want to seem like I'm dissing your tank--it's a beauty--but it probably requires a more substantial bottom panel design to stand the test of time(longer than it already has of course).

You need more surface area of structural silicone connecting the side panels to the bottom panel. This is why M M1A1 is suggesting a bottom internal brace the same thickness of the bottom. If you can firmly mount some glass strips along the front and bottom structural seams it will be as if you have two bottom plates connected to the sides, twice as much silicone to grab onto.

 

[M1A1]

How thick is the side glass? I don't see it mentioned or pictured anywhere in the thread.

 

[Trouser Cough]

Yes both but the integrity of the structural silicone seam was compromised by the hydrostatic force pushing the side panel out over time.

I'd be surprised if that were the case. It's more likely in my mind that I caused the issue.

The first in this series of leaks would have been my poor prior sealing job wherein a section of the sealant bead that I had installed was too thin and eventually leaked. That was when Peace River gravel was spotted between bead and glass. Likely any future issue would have been self inflicted as I had not considered that outward pressure might be held back by what I had thought was "cushion" caulking between panes. I should have removed silicone by first cutting downward on the side panes to preserve the integrity of that "structural" bead. Instead I removed the bead without care.

It's not like the water pressure shattered the bottom panel and as you've pointed out it's plenty strong enough to hold the water. The silicone was stretched OUT and then the bottom panel will do what anything does with gravity cause there's nothing holding it up anymore.

I'm not sure I agree w/ the order of operations but I definitely see what you mean and now see that my caveman way of removing the bead introduced a far larger problem. Bummer.

I've been dancing around saying this cause I don't want to seem like I'm dissing your tank--it's a beauty--but it probably requires a more substantial bottom panel design to stand the test of time(longer than it already has of course).

I am far from a delicate little flower and would prefer to understand your meaning absent politically correct speech. I promise not to be offended and I have a strong preference for objectivity. There is no such thing as someone expressing a negative opinion about my tank such that their opinion might shape mine... they're simply correct or not. I genuinely appreciate your concern but in a situation like thisI can't afford the luxury of kind speech. Hit me.

You need more surface area of structural silicone connecting the side panels to the bottom panel. This is why M M1A1 is suggesting a bottom internal brace the same thickness of the bottom. If you can firmly mount some glass strips along the front and bottom structural seams it will be as if you have two bottom plates connected to the sides, twice as much silicone to grab onto.

Hmmm... This makes sense now though I still wonder about deflection as I climb in and out of the tank. Maybe I should do that nearer a corner than the mid-point of the front pane?

 

[Trouser Cough]

How thick is the side glass? I don't see it mentioned or pictured anywhere in the thread.

Back shortly

(edit: 5/8")

 

[M1A1]

Yikes, that sounds low but I'll have to do the math. Are the rough dimensions 120" x 48" x 32" ?

 

[Backfromthedead]

Are the side panels stacked on the bottom??? Surely not in a tank this size. I've just been assuming it was a floating/inset bottom panel this whole time.

The long panels are only 5/8"???

If this tank does have stacked side panels than that means you actually only have a 5/8" structural bead to contend with roughly 1900-2000 lbs of force at the bottom of a full tank. That's assuming a water level of 30-31". I'm not gonna do all that math but imo it ain't enuff!

 

[Trouser Cough]

Are the side panels stacked on the bottom??? Surely not in a tank this size. I've just been assuming it was a floating/inset bottom panel this whole time.

I'm not familiar w/ the term "floating" as it might apply to a tank's bottom pane. It is the bottom pane that the side panes rest upon in this tank

long panels are only 5/8"???

If this tank does have stacked side panels than that means you actually only have a 5/8" structural bead to contend with roughly 1900-2000 lbs of force at the bottom of a full tank. That's assuming a water level of 30-31". I'm not gonna do all that math but imo it ain't enuff!

Gimme a sec and I'll measure the tank and knock the numbers out. My horseback calc is that the forces aren't quite that hight but probably not by a ton (hooo hah I crack me up)!

 

[Trouser Cough]

Ok... using exterior dimensions which are going to produce a generous result the force exerted by the internal volume and height:

F= 0.5 x.036x120x30.25^2

Hmmm... higher than I had guessed.

Outward force exerted on the front pane is 1976.5 #

Weight of water supported by bottom pane is 6800 #

The manufacturer sells this tank as an 800 gallon and I'm certain that is grossly out of line as well. I'll go run a couple more calcs and get that bottom pane weight number tightened up. Back in a sec.

(edit: roughly 730 gallons based on interior dimensions. That would put the weight of water-only on the bottom pane at roughly 6200 # )

 

[wednesday13]

Does the frame/trim come into play here at all? Like the old metaframe tanks, the glass isnt relying on the silicone alone to hold everything together. Is the trim just plastic or is it metal? Id think u could bolt angle iron or 2x4 around the outside of the tank down into ur wooden base to prevent any kind of bowing at the bottom panels.. Then ur silicone is just an inside seal as intended… even if the structural seals are compromised it wouldnt matter if it cant move… im an acrylic guy but my first acrylic tanks were metal frame and worked relying on the metal shell to hold very thin material in place.