New Acylic Tank Bulging at center

tom b.

tom b.

New Member
I have just purchased a new 500 gallon acylic tank that I have in my dining room. The tank is bulging at the center approx. 3/8". The tank builder has assured me that this is normal. The problem is that a week ago this same tank builder sold my contractor a tank that exploded on me dumping out 500 gallons of Saltwater, Sand, Live Rock, Coral, and fish. What a mess we had to clean up!!! I posted about this problem at the begining of the week but at that time I did not have the new tank installed. The tank is filled again with saltwater, live rock, coral (no fish yet).
Has anyone out there heard of a acylic tank of this size bulging at the middle. My additional problem is I am going out of the country for a week leaving this Sunday and knowing how I am I will be calling home everyday to check on the tank.
Can anyone help me sleep better??
 
robchuck

robchuck

Active Member
I wouldn't say that it's "normal" for an acrylic tank to bow, but there are quite a few manufacturers out there that build acrylic tanks to minimal standards that bow; but 3/8" is quite a bit. There are quite a few factors that come in to play that cause bowing, especially with larger tall tanks using the minimal thickness of acrylic.
What are the dimensions of your tank, and what thickness of acrylic was used to build it?
Unfortunately, knowing that your contractor's tank from the same builder exploded wouldn't help me to sleep too well. I would immediately discuss the situation with the tank builder, as 3/8" of a bow would be unacceptable in my book.
For what it's worth, I have a 24" tall 300g acrylic tank built out of 1/2" acrylic and have no bowing. When I was shopping vendors, several of them recommended 3/4" to prevent any bowing from occuring.
 
robchuck

robchuck

Active Member
By the way, how do the glued joints of the tank appear? Can you see any bubbles in the seams?
 
tom b.

tom b.

New Member
The tank is 60"L X 56"H X 52"W. The acylic is 1 1/4" thick. The Glue all looks good, no bubbles etc. The contractor who I purchased the installation from services several tanks of this size in the area and he checked one yesterday and said it had a bow in the center.
Any other suggestions??
Thanks,
TOM B.
 
pontius

pontius

Active Member
actually it IS pretty normal for acrylic tanks to bulge a little.
sorry if you posted this already, but how thick is the acrylic panels, and how is it all connected at the top? acrylic bulges, it is not as hard as glass. if it is of a proper thickness though, it will not matter at all. 3/8" is not that much, imo.
also, I'm sure you know this already, but with an acrylic tank, the stand MUST be covered at the top. in other words, the tank must be sitting solidly on a single piece of wood with no openings. where this is not at all necessary with glass tanks.
 
tom b.

tom b.

New Member
The top is connected (Supported) with four 1 1/4" thick X 12" Wide peices of acrylic.
The cabinet it sits on is well constructed with many horzontal & vertical 2"X 4". The first tank was not on foam but this tanks sits on 2"fome. We have it perfectly level. The first tank was about 1/4" off from being level.
Your posts makes me feel better. Do you have a large tank or have friends that have a large tank. Normally you don't see a tank this large except in comercial sites. I got the bright idea to install this tank where a window was between the dining room and the outside porch. (we are enclosing the porch and it will have AC) I live in Naples, Florida
Thanks, and please let me know of any other suggestions you might have.
Tom B.
 
pontius

pontius

Active Member
Originally Posted by TOM B.
Your posts makes me feel better. Do you have a large tank or have friends that have a large tank. Normally you don't see a tank this large except in comercial sites. I got the bright idea to install this tank where a window was between the dining room and the outside porch. (we are enclosing the porch and it will have AC) [/B] I live in Naples, Florida
do I have a large tank compared to yours? no. mine is 125 gallon acrylic and I also have a sump/fuge that is 65 gallon acrylic. I would guess the panels in my 125 are about an inch thick, and it bulges a little. a little bulging should be expected with acrylic. acrylic can take more pressure and impact than glass. as long as it is level and sitting on a solid stand top.
 
acrylic51

acrylic51

Active Member
I do know you will get some deflection in acrylic tanks, but IMO 3/8" seem like an awful lot for 1 1/4" acrylic. If I'm understanding how the tank was braced at the top your saying it's basically 4 separate 1 1/4"x12" wide pieces connecting the front to the back and sides.....Basically your saying he glued 4 pieces to the top of the tank? If that's the cause I would take the tank back.....The top panel where the tank is "eurobraced" should have been done out of 1 solid piece of acrylic and the openings in the top of the tank should have been routed in.......
Please tell us is it 4 separate pieces?
The top should be routed something of this nature

 
aw2

aw2

Active Member
Tom,
It honestly sounds to me that you got a shady tank builder. I hope to God that you dont end up with another 500gal. of water, rock, sand and coral on your floor.
On 1.5" acrylic, even on your size tank, I would expect it not to bow AT ALL.
 
dogstar

dogstar

Active Member
IMO from the size of the panels you will get so bowing. A typical tank is long but not as deep and that leaves less area without support from the other panels. But you tank being allmost square gives no support from the other panels in the center.
 
gregzbobo

gregzbobo

Member
put a straightedge (ruler or level) along the front of a glass tank and you will notice that it is somewhat bowed, acrylic will bow as well.
 
tom b.

tom b.

New Member
The tank was made of two sides, two back & Fronts, and one bottom solid pieces. Then he took the 4 pieces of acylic and glued them apart about 15" from each other leaving enough room for him to get inside the tank when necessary. The bottom of the tank has an additional support in that he used a strip of Acrylic 1 1/4" X 2 1/4" completely around the botton inside of the tank.
There was no routing of any of the panels. Taking the tank back would present a huge problem as the Contractor would not be able to get any satisfaction from the builder. I will have over $20,000.00 in the installation + the cost of the fish.
This is the fourth day and the water is still in the tank and it isn't bulging anymor than before.
If I had to do it over again I wouldn't as it has been a pain in the (you know what)!!
Tom B.
 
tom b.

tom b.

New Member
Doesn't sound good to me also. I asked why they didn't use a router to fit the peices and the contractor (not the tank builder) said that "sounds like a good idea".
I know I probably made a mistake using these folks!!!
 
guppy slayer

guppy slayer

Member
My 50 gal. acrylic bows in the front. Maybe just as much as your 500 gal. I don't know exactly but the acrylic is no more than 2/8" thick. The top is a solid, routed piece. It's been holding water for a long time. I've had it for about 3 1/2 years and my brother-in-law had it before that. I say the bowing is normal. Good luck with your 500
 
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