# Tank Construction Question



## justneed2 (Feb 14, 2008)

Hi All,

I am new to the forums and just getting back into the hobby, with that said here's my situation.

I bought a used 110 gallon (48" long x 30" tall x 18" deep) glass aquarium. The plastic trim pieces are shot and I am thinking about building custom wood trim and bracing to replace the plastic as it will look nicer and it will also add structural support the plastic can't.

When I picked the tank up it was empty, but dirty. After cleaning it up I found some of the silicone seals inside look a little questionable so I am going to reseal them. No problem right? Plenty of articles out there with DIY info on that.

Here's where I run into problems.

After removing the bottom plastic pieces I noticed the tank is not constructed how I anticipated. Rather than the walls sitting on the bottom pane, the bottom pane sits inside of the walls. There was then a border of 1/2" thick glass (approx 2" wide) placed around the entire edge of the tank.

This means that the center of the tank when resting on a flat surface is not supported, only the outside edges. Should I be concerned? Should I build a stand that has a recess to allow the border to sit in the stand, thus allowing the center of the tank to sit flush on a flat wood surface?

Any help would be appreciated. The person I bought the tank from said they never had any problems, but they were using it for a freshwater setup, and I am building a reef aquarium.

I am concerned that adding live rock will put to much stress in an unsupported area of the tank.

I have tried searching for tank construction methods, and everything I have come across so far says the entire bottom pane should sit flush.

Did I buy a bum tank?


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## herefishy (Dec 14, 2006)

If you happen to know the manufacturer of the tank, Perfecto, AllGlass...., you may be able to contact them for replacement trim.[/i]


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## justneed2 (Feb 14, 2008)

Any thoughts on the way the tank was actually constructed?


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## herefishy (Dec 14, 2006)

Well, I have never had to tear one of my tanks down that far. I would think that the construction seems to be sound. 

As far as reinforcing the center, per your fears, may be accomplished by the stand or cabinet. My cabinets for all of my large tanks have a piece or two or three running transverse to the length of the cabinet. The trim on the top would also reinforce the top from pulling out. My 300g tanks, which are 8' long, actually use (4) 24" glass canopies. As does the 250g. I just looked and the 6' tanks use (3) canopies. 

You should be able to google up Aqueon, who is now the conglomerate that distributes Perfecto or All-Glass, and see what the configuation of the support of their tanks looks like. If you could contact the previous owner of your tank, he may be able to tell you who the manufacturer may be.


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## porksnorkel (Oct 6, 2006)

glass tanks are intentionally manufactured to have all the tanks weight and everything in it, supported at the 4 corners of the tank. if u are concerned about the weight of the rock in the center of the tank, just pick up some of that egg crate lighting cover stuff at the hardware store. this will help spread the load out. take a look at mine...










easy to cut too...


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## justneed2 (Feb 14, 2008)

Thanks for all the info!

I can definitely use it as I work on rehabbing this tank. And the egg crate style support is a good idea, one I would not have thought of.

If anyone else has anything to add, please feel free as I will continue to monitor this post as I progress through this project.

When I switch from research and planning to actually executing i will try and document the project as I go - maybe down the line someone else will benefit from it.


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## herefishy (Dec 14, 2006)

porksnorkel said:


> glass tanks are intentionally manufactured to have all the tanks weight and everything in it, supported at the 4 corners of the tank. if u are concerned about the weight of the rock in the center of the tank, just pick up some of that egg crate lighting cover stuff at the hardware store. this will help spread the load out. take a look at mine...


I think that this may not be so. I think that they are engineered so that the weight is to be supported by the perimeter of the tank. If you look and the construction of all cabinets and metal stands, they are constructed to support the perimeter of the tank. This is particularly evident when looking at metal stands. If the above were true all you would need is (4) legs. 
Deflection is a tanks worst enemy. Deflection is the "bowing" effect cause by the gravitation pull on a given weight on a linear object. I am sure you have seen concrete road trusses or metal roof trusses that are "cambered" so that when loaded, they "flatten" out when a load is applied. The best way to demonstrate deflection is to get a straw, support both ends and push down in the middle. That spells doom for aquariums as the glue seal is not one that is capable of such flexing. If one wanted to reinforce the tank, one should make sure that a.) all forces are directed to the perimeter of the tank , b.) the perimeter is reinforced, and c.) the bottom and center of the tank are supported in such a way as to prevent any type of deflection or "bowing".

Just my observations here.


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## justneed2 (Feb 14, 2008)

> glass tanks are intentionally manufactured to have all the tanks weight and everything in it, supported at the 4 corners of the tank.





> I think that they are engineered so that the weight is to be supported by the perimeter of the tank.


The tank I am working on is supported around the entire perimeter of the bottom. My concern, not having been in the hobby for awhile, was that the bottom should be sitting flush and not only supported at the perimeter.

Based on both of your answers it looks as though the way the bottom of my tank is constructed is correct.


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## fish_4_all (Nov 13, 2006)

I have never seen a tank that did not have the bottom of the tank at least 1/4 inch if not 1 inch above the base. 10 gallon all the way up to a 225. I have also seen most sites that give instructions to DIY tanks give the same instruction. 

The reason is that if you have nothing under the bottom of the tnak there should not be anywhere for a pressure point. The bottom will bow very little because the sides are rigid and holding it firm. If the bottom touches a flat surface, if the surface has any defects this can cause a pressure point and a major failure. 

It is perfectly normal to see tanks constructed this way. There are some who will construct them so the sides are on the bottom and swear by it. A large dense peice of foam is then used to support the bottom so that the bottom can flex in on the foam and not create a pressure point. For me, the easier the better so when I make my tanks I will be making them with raised bottoms.

As for making your own molding, wood should work fine as long as it is sealed before using it to prevent swelling and roting. Is what I plan to use when I make my tanks, if I ever get to.


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## porksnorkel (Oct 6, 2006)

herefishy said:


> porksnorkel said:
> 
> 
> > glass tanks are intentionally manufactured to have all the tanks weight and everything in it, supported at the 4 corners of the tank. if u are concerned about the weight of the rock in the center of the tank, just pick up some of that egg crate lighting cover stuff at the hardware store. this will help spread the load out. take a look at mine...
> ...


Regardless...we can agree, as fish 4 says, that the bottom pane should not touch solid surface. at least on American style tanks. Euro manufacturers use the foam and braceless design as mentioned.


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