<a href=showthread.php?s=&postid=9843891#post9843891 target=_blank>Originally posted</a> by spazz
below you will find the recomended thickenss for that aquarium. this calculator is from the cyro wesite. that tank will end up with a noticable bow in it over time. im not sure who is building that tank but they should have used at least 3/4" acrylic if not 1" acrylic for the fornt and back. the sides could have been 3/4" and the top and bottom could have been 1/2" acrylic. you may not have any problems with the tank bursting but it will bow. there is no doubt in my mind of that because of how long the tank is.
H Enter Height of Tank [in] 24
L Enter Length of Tank [in] 119
Is the top closed ? (yes or no) yes
q Maximum Water Pressure [psi] 0.8664
L/H L/H 4.958333333
a Maximum Allowable Stress for Acrylite GP in Aquarium [psi] 750
b b 0.94
Tc Thickness of Sheet required with top [in] 0.791
This aquarium, and four prior to this have been built by The Aquarium Company in Winthrop, MN. Spazz, you haven't been the first to question the thickness of the tank and I thought that I would send off your thoughts directly to the builder for his comments. I thought that I would post his reply to me for others to see.
"Lot of armchair aquarium builders out there. It never ceases to amaze me the number of "experts" that present themselves in fields where they have very limited working knowledge or experience. You have nothing to worry about on your aquarium. The bow you see right now is what you will see 5-10 years from now. The bow and flex reaches its maximum at about 3.2X the height of the material ie. the bow of a 24" tank reaches its maximum flex at about 77", this is from Rorke, the military spec data on materials stress and strain, materials with a fixed top and bottom. As for the calculator, it just doesn't fit for your construction. First, it is for a two part polymerized joint, not solvent. The polymerized joints in real world use, just are not as strong or durable and do require thicker materials. Second, it does not figure for a Euro-Brace. There are dynamics with this that are not addressed. Third, it figures for a 750 PSI allowance on a joint that will see about .85 psi. Also, this spreadsheet formula has nothing to do with bow, and bow is what your expert derives from the formula. These are flawed conclusions drawn from inaccurate information from a non-applicable formula. Chuck, I just don't know how to nicely word this for a Reef-Central response with-out being drawn into some web drama with the rest of the web experts.
Let me share with you one of my favorite flawed conclusions, which unlike above, is actually based on ACCURATE statistical information.
"Everyone has only a 50% chance of every dying."
Half of the population of mankind that has lived on earth, since the beginning of mankind, is alive today. The population of man on this earth is an exponential formula. This statement is true, half of the total population that has ever lived is alive today. Can you therefore draw the conclusion that you only have a 50% chance of death? If half the people that have ever lived on earth are still alive today than you could argue the point. As ridiculous as this sounds, it is statistically true. Of course there are dynamics and conditions not addressed that make this statistical formula flawed. It kind of reminds me of your aquarium "experts"."
When I asked for a quote for building this tank, I didn't specify any thickness of acrylic. I left that up to the builder. Another aquarium builder in MN, gave me a quote for the same sized tank and his quote also called for 1/2" acrylic sides. As it stands, the tank looks great! Still holding water and if there is a bow, I sure have a hard time seeing it. I'm not an expert in aquarium building, acrylic properties, or mathematics, so I am going to sit back and enjoy the tank...........
