Rimless Tank Bowing

[sus]

I had a custom tank built and during my first leak test today I noticed the front pane was bowing. I put a tape on it and was measuring 1/8"-3/16" deflection in the center. This is obviously concerning and I'm hoping someone can chime in and tell me it's "normal" and nothing to worry about?

Tank Specs:
60"x24"x18" rimless
1/2" (12mm) thick starfire on 3 sides
PVC bottom

 

[andrek787]

I had a custom tank built and during my first leak test today I noticed the front pane was bowing. I put a tape on it and was measuring 1/8"-3/16" deflection in the center. This is obviously concerning and I'm hoping someone can chime in and tell me it's "normal" and nothing to worry about?

Tank Specs:
60"x24"x18" rimless
1/2" (12mm) thick starfire on 3 sides
PVC bottom

Any sort of bowing is not acceptable. I believe the minimum glass thickness for 60" long rimless is 5/8" if tank is more then 16" tall. You best bet is to add a glass center brace or go full eurobracing.

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[sus]

Any sort of bowing is not acceptable. I believe the minimum glass thickness for 60" long rimless is 5/8" if tank is more then 16" tall. You best bet is to add a glass center brace or go full eurobracing.

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What are you basing this on? Is there some sort of calculation or is this just your opinion?

 

[moondoggy4]

Acrylic tanks bow glass tanks should not I would not put any livestock in it I would return it.

 

[andrek787]

This is based on talking to a few custom aquarium builders about getting a custom 60" long rimless tank made. Planet Aquarium, Red Sea, SCA and Elos 60" long rimless tanks are either 5/8" or 3/4" thick glass. Reefsavy's site lists in the FAQ the maximum tank dimensions for each glass thickness, 1/2" is limited to 17" on 60" long tanks. If you do a search, there are a number of threads about bowing/stress issues with 60"L 1/2" thick rimless tanks.

 

[Ou8me2]

Rimless tanks use thicker than normal glass to deal with not having braces. They should have used thicker glass for sure. It's definitely something you should be worrying about and not normal.

 

[Reef Dude]

If you can't return it, you could consider installing eurobracing. You could also consider lowering the overflow height to lower the water level in the tank to help reduce the pressure. Neither of these are ideal, I know, but I was just thinking of ways to salvage the situation if you can't return the tank. Or you could roll the dice and use the tank... Bowing is not a good sign, but the tank may never fail. I wouldn't do this though and I wouldn't want to worry about it all the time. I feel for you... The same thing happened to me... I bought a rimless tank assuming that the manufacturer knew what they were doing, and it wasn't until I saw bowing then researched a lot on RC that I realized the tank was under built.

 

[sus]

This is based on talking to a few custom aquarium builders about getting a custom 60" long rimless tank made. Planet Aquarium, Red Sea, SCA and Elos 60" long rimless tanks are either 5/8" or 3/4" thick glass. Reefsavy's site lists in the FAQ the maximum tank dimensions for each glass thickness, 1/2" is limited to 17" on 60" long tanks. If you do a search, there are a number of threads about bowing/stress issues with 60"L 1/2" thick rimless tanks.

Interesting, the tank is from planet aquariums so I'm not sure what to say about that. Also, the height of the water from the inside (on top of the pvc bottom) is only 16"

 

[sus]

If you can't return it, you could consider installing eurobracing. You could also consider lowering the overflow height to lower the water level in the tank to help reduce the pressure. Neither of these are ideal, I know, but I was just thinking of ways to salvage the situation if you can't return the tank. Or you could roll the dice and use the tank... Bowing is not a good sign, but the tank may never fail. I wouldn't do this though and I wouldn't want to worry about it all the time. I feel for you... The same thing happened to me... I bought a rimless tank assuming that the manufacturer knew what they were doing, and it wasn't until I saw bowing then researched a lot on RC that I realized the tank was under built.

Well, I definitely can't return it. And the annoying part is that they originally sent me a eurobraced tank, and it wasn't what I wanted or ordered so I sent it back. So now to have to pay to add eurobracing pretty annoying

 

[RegalAngel]

In 1976 I had a 125g glass tank with no top bracing. It bowed at least 3/4" centerline and never had any problems until I sold it 6 years later.

 

[sus]

This is based on talking to a few custom aquarium builders about getting a custom 60" long rimless tank made. Planet Aquarium, Red Sea, SCA and Elos 60" long rimless tanks are either 5/8" or 3/4" thick glass. Reefsavy's site lists in the FAQ the maximum tank dimensions for each glass thickness, 1/2" is limited to 17" on 60" long tanks. If you do a search, there are a number of threads about bowing/stress issues with 60"L 1/2" thick rimless tanks.

Also, digging through old emails, my quote from reefsavvy was also for 1/2" glass. They told me once they go to 20"high they switch to 3/4" as I was debating that height at one time...

 

[ReefCowboy]

A bowing tank is a risk you are willing to take. I understand your situation and remember that it can end up being fine, but will you really enjoy the tank constantly thinking you could come home to a disaster?
I would eurobrace it, cost would be small, it still allows the tank to look sharp, and most important...peace of mind

 

[Reef Dude]

Adding eurobracing would be a pretty easy and cheap to diy. Figure out the size/thickness you want, get a local glass shop to cut to size, and then silicon them in yourself. Eurobracing looks pretty nice, and it offers some other advantages such as not having to worry about water splashing out of the tank when using a magnet to clean the glass.

 

[sus]

Adding eurobracing would be a pretty easy and cheap to diy. Figure out the size/thickness you want, get a local glass shop to cut to size, and then silicon them in yourself. Eurobracing looks pretty nice, and it offers some other advantages such as not having to worry about water splashing out of the tank when using a magnet to clean the glass.

Yeah, I know it would be a fairly easy/cheap mod but it just defeats the purpose of going with the rimless look... like I said, they (planet aquariums) originally sent me the wrong tank that had Eurobracing and I sent it back because i wanted a sleek rimless tank...

 

[ca1ore]

Two things. First, eyeballing a 1/8" deflection is impressive; must have been an eagle in a prior life. Second, I'd suggest it's nothing to worry about. My deep blue frag tank (48" length) bows by 1/8" in the middle (it's 8 mm glass I believe) and it's going on 4 years setup. Ask the builder if you're nervous; I'd certainly not be futzing around with braces. Also, how did you measure it? If you simply measured the width of tank at the mid point, remember that each of the long panels will bow equally, so if measure is 1/8" then each panel is actually only bowing by 1/16". I think you're worrying unnecessarily (and getting bad advice).

FWIW, I bet most folks with rimless tanks would find a bow by putting a tape measure on it

 

[sus]

Two things. First, eyeballing a 1/8" deflection is impressive; must have been an eagle in a prior life. Second, id suggest it's nothing to worry about. My deep blue frag tank (48" length) bows by 1/8" in the middle (it's 8 mm glass I believe) and it's going on 4 years setup. Ask the builder if you're nervous; I'd certainly not be futzing around with braces.

No eyeballing, I used a tape measure...

That's good to hear you have 1/8" and no issues

 

[ca1ore]

No eyeballing, I used a tape measure...

That's good to hear you have 1/8" and no issues

Modified my post. If u used a tape measure panel deflection is only half because there are two panels.

 

[sus]

Modified my post. If u used a tape measure panel deflection is only half because there are two panels.

Makes sense. Thanks for the input!

 

[andrek787]

Interesting, the tank is from planet aquariums so I'm not sure what to say about that. Also, the height of the water from the inside (on top of the pvc bottom) is only 16"

I guess the safety margins got relaxed to keep the costs under control. It was a couple of years ago.

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[Vinny Kreyling]

Years back Odell made my 220 without any braces, standard practice with 5/8 glass.They supplied glass covers & tracks.
Instructions Clearly Stated -- do not cut plastic tracks until tank is full otherwise they will fall in when tank is filled.
So- tanks can & will bow but are still safe.