Question About Building Glass Aquarium

[Rockfella]

I am not mistaken. This debate has been going on for many years in many forums. It doesn't matter if I used to work for an aquarium builder as a line assembler. It doesn't matter if I regularly visit my very good friend Russ at his glass shop and talk about this very thing and why he has stopped the floating design when he is commissioned to build an aquarium. It doesn't matter that the only failures I have had with tanks I have bought were floating bottom design, with and without foam. All the aquariums I have built, including my 500g acrylic (yeah, I said acrylic) have been a success, except the 125 I built as a floating bottom.
I'm not talking from my ass about this subject and I'm not just msking it up as I go along. I have been in this hobby for 40 years and 10 of those were a business.
This debate is going to end for some people when their floating design fails and some people will never experience a fail in their entire fish keeping life. Others will experience constant fails with glass tanks and switch to acrylic and swear by that construction. And then there will be those of us, myself included, that have experienced fails in both designs and both materials but continue to persue the hobby because that is just part of the hobby.
I would suggest, and just my opinion, construction of your own aquarium be done in a clean, well lit dedicated area and have a concise, well thought out plan before during and after construction.
But, be prepared for catastrophic failure at least as something that could happen and sometimes does even to the best construction.
This debate, like the add-salt-to-freshwater debate, the should-I-use-a-bubbler debate, is-bare-bottom-better-than-substrate debate are never ever going to be resolved or "won" because there are too many people with too many experiences, too many variables and too many opinions.
Do the best you can and make the best determination based on your gut feeling and just go with that prepared to accept whatever happens after......or doesn't happen.
...out

Of all the tanks let's say 500 you've build how many of them were properly braced on the top front to back in the middle?

 

[wayada]

I came across this old thread while doing some other research. I would normally just state my opinion and move along, and not pick out one poster's opinion and quote it's deficiencies, but there are so many wrong assumptions here on square glass vessels with silicone joints that I feel compelled to comment and seeing the poster hasn't been seen in the forum in about a decade, hopefully no harm no foul and no hurt feelings. But if still around, I welcome the retort. I will also add that perusing the poster's other comments throughout the forum, he has made some comments that were intelligent and seemed of sound background, while others comments...well...not so much, and others that had an apparent Dunning-Kruger level of arrogance. Nonetheless, I thought I would put in my two cents in case another comes across this post doing research.

The floating bottom design is actually prone to failure for several reasons.
The most obvious is the weight of all the water in the tank is being held by the silicone on the bottom pane of glass.

I am not sure what he is thinking by "floating bottom". If he is thinking an "elevated bottom" then this statement is correct. But I don't believe that is what the OP was getting at. A floating bottom to me and I believe to most is a bottom that sets inside of the side panes of glass but is not elevated above the bottom edge of the side panes, it sets flush. With this assumption of the OP, the only way the silicone is supporting the weight of the water is if the tank was suspended with zero bottom support from a stand. Can't say I have ever seen that. Note: To avoid confusion, when I refer to side panes, I am referencing all four sides of the tank unless noted otherwise.

A not so obvious reason for failure is the fact that, in addition to the water weight, decor and substrate, any upward force would have an equal stress factor....like when people put styrofoam under their tanks.

The addition of items in your aquascape is going to have relatively little difference in mass when considering the total volume of water of a large tank. While most of these things are heavier than the water, they also displace water. ie a cubic foot of gravel or sand is only about 35lbs heavier than a cubic foot of water. So when 100lbs of gravel to your tank you are displacing about 65lbs of water and only increasing the total weight of the filled aquarium by roughly 35lbs.

Placing the sides of the tank on top of the bottom piece actually gives you more surface area to apply silicone.

This would only be true if the side panes were thicker than the bottom. Tank geometry dependent, it is more likely that the bottom glass would be thicker if not the same thickness as the side panes.

Placing the end glass inside the front and rear panels is a matter of opinion and I am of the opinion that strength isn't the reason

No, not entirely a matter of opinion. Opinion may come in on which way would like better, but sandwiching the right and left sides between the front and back provide for a stronger silicone joint for the front and back where it is most needed. ( Front and Back are assumed to be the longer two sides of the aquarium) This has to do with the tensile vs. shear strength of a silicone joint (discussed later)

glass is purchased in standard lengths and having to remove an inch from a 36", 48", 60", 72"....etc...is more work

Manufacturers purchase glass in pieces as large as 20 feet by 10.5 feet and rarely order glass in ready cut sizes, if ever. Nearly every piece of glass for an aquarium is cut to size at the manufacturer. So whether it is an inch or a foot it makes no difference.

Everything that is done to commercial built tanks is done for two reasons mainly:
-Build cost
-Liability
Liability is a risk factor that determines how the manufacturer builds the tank and they go by industry standard and experienced past failures.

This is somewhat accurate. Large scale, profit driven companies first look at build cost. Liability is often secondary. You only need to look at the number of product recalls ( any, not just aquariums) that there are where the manufacture knew that a deficiency existed and only corrected the issue once it started costing them more to ignore it than fix it. ( via returns, lawsuits, government fines, etc.) The point here is don't rely on profit driven companies, the so called experts, for doing things right. Often they are doing things that are "just good enough."

First of all...tensile strength is how much silicone will stretch,

While tensile strength and stretch are related in that they are both measured in a tensile test, they are NOT the same thing. Tensile is measured as force (psi) and stretch is measured in a percentage of elongation.

Placing the glass under the sides allows tensile strength to keep the sides, front and back from separating...

There is confusion here on what tensile strength is. With the "glass under the sides" the joint is experiencing shear stress NOT tensile stress.

therfore, the silicone used in the corners and "tooled" with the finger or actual tool is what would stretch when pressure is exerted from the inside.

The important part of the silicone joint is what lies between the glass pieces not the amount that is "tooled" along the sides or bottom and is what is known as a safety fillet. "With the side panes mounted on top of the bottom pane as he suggests", the silicone "tooled" onto the sides adds little to nothing to the joint strength. The fillet of silicone on the inside of some aquariums mainly functions to protect the structural silicone joint from damage and does add some leak protection insurance. But if your tank is going to leak without the fillet, there are bigger issues to worry about.
Also in this configuration the joint is under going shear stress and therefore stretch has no role as they are fundamentally different.

There are multiple tank manufactures building high end rimless tanks with minimal or no silicone fillet on the inside of the tank: ADA, Red Reef, UNS, Lifegard Aquatics, Aquarium Masters. Being high end tanks with good reputations and focusing on quality I feel justified in mentioning them here.

I am not mistaken.

Yes he is, on almost every front.

It doesn't matter if I used to work for an aquarium builder as a line assembler. It doesn't matter if I regularly visit my very good friend Russ at his glass shop and talk about this very thing and why he has stopped the floating design when he is commissioned to build an aquarium. It doesn't matter that the only failures I have had with tanks I have bought were floating bottom design, with and without foam. All the aquariums I have built, including my 500g acrylic (yeah, I said acrylic) have been a success, except the 125 I built as a floating bottom.
I'm not talking from my ass about this subject and I'm not just msking it up as I go along. I have been in this hobby for 40 years and 10 of those were a business.

While I am happy for him to go visit his good friend Russ and bond (pun intended), but that is anecdotal at best. I can relate this entire comment to the following I had with someone with years of "experience" in their field. I switched plow companies ( that's snow plowing, for those not blessed with the frozen precipitation) anyway...he was not doing a very good job and I suggested to him that he could do it another way, a way that would not only be quicker but produce a better end result. His response was " I've been doing this for twenty years, I think I know what I am doing. What experience do you have?" I said none ... other that watching this be plowed for more than twenty years, if you want the contract next year give it a try or do a better job anyway you see fit. " He did and agreed in the end. Moral of this story is, 20 years experience doesn't mean squat if you have been doing it wrong for 20 years and never think you know everything about anything regardless of your past experiences.

All the aquariums I have built, including my 500g acrylic (yeah, I said acrylic) have been a success, except the 125 I built as a floating bottom.

Because he mentions acrylic here I will note that the adhesives used with acrylic tanks have a much higher shear strength than tensile strength. Based off of that and that acrylic tanks I believe are all rimless(?), I would assume they should be made with sides on top of bottom, all else being held equal.

Silicone adhesive has a much higher tensile strength than shear strength. When looking at only joint strength relative to the forces applied by the water contained, Logic would suggest that you build the aquarium in such a way to take advantage of the strengths of whatever adhesive you are using. With a glass tank, the largest forces on the silicone joints of an aquarium are found on the joints of the longest sides, (elevated bottom or floating bottom with no support excluded). With that you would want the silicone joints of those sides to be experiencing a tensile force rather than a shear force. For this to happen, the longest sides(front/back) have be along the side of the bottom and the shorter sides(right/left) should also be along the sides of the bottom and sandwiched between the front and back. This method gives the front and back that are under the greater force, three joints that are experiencing tensile stress. And the shorter right and left sides have joint at the bottom under tensile stress and shear stress from top to bottom where not as much strength is needed. Some might suggest to do all joints at 45 degree angles then. While this will maximize the shear strength of the joint it will halve the tensile strength of the joint resulting in an overall weaker joint.

With all that said you can build an aquarium with the sides on the bottom and be successful if the forces in the tank do not exceed the shear stress of the silicone joint. With rimmed tanks the type of joint matters even less as forces along the bottom joint aid significantly by the trim, even beyond what the silicone can hold. So for production rimmed tank I would assume many if not most are made with sides on top of the bottom for ease of production with having the support of the trim.

Don't take my word on anything...double check all your research from multiple sources. For as you know I just making sheet up...I'm not but you don't know that. Or I could just be wrong in my assumptions.


Some unrelated gems:

Remember, water is a very poor conductor of electricity, so worrying about stray voltage is easily remedied by the addition of a grounding probe....
I have had significant voltage detected in the tank disappear completely with grounding probes.

First, only pure water is a poor conductor of electricity, but we are never talking about pure water in this hobby. Aquarium water with its salts, minerals and whatever else makes up the TDS, make aquarium water a nice conductor of electricity.

Stray voltage is not easily remedied by grounding probes. The only thing grounding probes are doing in that case is hiding a problem that shouldn't be hidden. Ground probes should be a safety net, not a solution.

I am a firm believer that the people that surround me are morans. Sheeple. The Clueless Mass.

Anybody find the ironical humor in moron being misspelled in that statement. I never met the person but I am guessing I could find is picture in a Dunning-Kruger article. IDK ... just sayin'


A sign of intelligence is always considering the possibility that you may be wrong...stay humble my friends.