Acceptable Bow on a 225 Acrylic?

Sara B · #1 09/27/2006, 05:57 PM

I have recently purchased a used 225 gallon Clarity Plus Acrylic tank that was a little over a year old. We were in the process of filling it and mixing in salt when the bow was noticed in the front of the tank. The tank appears to be bowing out about 3/4 of an inch. It was drained back to half full as the person who is helping set it up for me did not feel comfortable leaving it that way while I am on vacation. I have not owed Acrylic tanks in the past, so I am also not sure what would be acceptable for bow. Please let me know what range is acceptable for bow or if I should be shopping for a new tank.

Thanks,

Sara

Sara B · #2 09/27/2006, 06:02 PM

Here's a bit more information I just received in email ...

Eyeball the tank length wise and it bulges out like an old TV screen does. By eyeball it looks like it pushes out 3/4" in the center from the sides and top to bottom based off of the molding which is 3/4 thick. If that is not all, the back is pushing out too but this is from the center to the left side of the tank.

Biodragen · #3 09/27/2006, 07:17 PM

Don't forget that it flexes with a wave box operating which adds to stress.

Also there is some spots where you can see like cracks spidered out if you will. This is not noticable directly but more on an angle.

Acrylics · #4 09/27/2006, 07:18 PM

Not good IMHO. Not knowing the dimensions but thinking it can't be more than 30" high - I'd say 1/8 - 3/16" (bowing) *max*. I completely agree with your helper, not comfortable at all with that much deflection.
Either the tank is made from material which is far too thin or something else is wrong with it. Maybe the top joint separated or crossbrace popped?

HTH,
James

Biodragen · #5 09/27/2006, 07:22 PM

This is a 225 g that is 6ft wide 2ft deep and I think 30" high.

I am the one doing this set up for her.

I can tell ya the material is thicker on top and bottom( I think 5/8" and the sides appear to be 1/2"

Biodragen · #6 09/27/2006, 07:23 PM

Oh and apparently this tank is about 2 years old I think.
A wave box was run on it for two weeks.

Even with the tank half full the lower half bows out still.
The seams are mint and no bad signs there. The top is fine and the bottom is fine also.
This sits on a flat surface on the stand with 1/4 pink foam to help with any uneveness and prevent from a pinch somewhere.
I was told you need to do this with large tanks for the bottom.

Acrylics · #7 09/27/2006, 07:24 PM

Check the top crossbrace (front & back of it) and the joint where the top and front panels meet. That simply shouldn't bow that much.

HTH,
James

Biodragen · #8 09/27/2006, 07:27 PM

I did--we crossed in posts

Acrylics · #9 09/27/2006, 07:28 PM

IME, waveboxes require tanks to be built beyond "normal" specifications, overbuilt if you will. This goes for both acrylic & glass IME. If it's 1/2" on the vertical panels, it's underbuilt IMO anyway. Given the addition of the wavebox, definitely underbuilt.
Again, JMHO.

James

Biodragen · #10 09/27/2006, 07:40 PM

So is this tank with the described issues no good for use even without the wave box.

checkinhawk · #11 09/27/2006, 07:44 PM

you said the tank is 6ft long and 30in high,thats alot of surface area for 1/2" acrylic to handle that amount of water.a tank that size should be minimum 1" all the way around.

Vamp1975 · #12 09/27/2006, 07:56 PM

I overbuilt mine for this reason, I went with all 1-1/4" acrylic.

Acrylics · #13 09/27/2006, 08:35 PM

IMHO 3/4" with perimeter bracing & a coupla crossbraces is fine as it will yield ~1/8" deflection. Thicker material gives more options; fewer - larger openings or eurobraced only (no crossbracing).

I am not sure I would say the tank is "useless", just not useful as display quality, esp with the wavebox. I know you're gonna hate to hear this but maybe a large sump? Frag tank in the garage? Quarantine tank? This sorta thing.

Sorry 'bout that, now I feel bad

James

reefez · #14 09/27/2006, 09:51 PM

Excelent advice from someone who I would not hessitate to listen to.

Biodragen · #15 09/27/2006, 10:53 PM

I will measure the thickness in the morning when I can stop by to be sure.
It looks like 1/2 sides and 5/8 top and bottom.

I am just glad I spotted this when I did before Sara got too far for a disater to happen.

She has damn good flow in the tank and to add the wave box would be a real nice set up for a SPS only tank.
She is doing this right and nice and easy pace.
This is one darn thing that puts a damper in it.
I know this is a brand tank and the label is pretty much worn away I can't tell the make anymore.

As for the thickeness you ppl describe I take it this is for acrylic.
what about for glass?

Also what kinds price range would be expected to get a good tank that can handle what she has going on?

UCanDoIt · #16 09/27/2006, 11:26 PM

Usually 30"H tank with 72"L needs at least 5/8" or 3/4" on front and top so the display looks good w/o the appearance of bowing. All other sides can be 1/2". If the back bows on 1/2", it's no big deal as no one looks at the back of the tank if it's against the wall. The bottom and sides don't bow, panel too small on sides and the bottom is supported by the stand and not seen.

I don't think there's any worries about the tank leaking or exploding, as long as the original seams were done well. Bowing on a front panel that is too thin is natural, doesn't look good. All of TruVu's old tanks use to do exactly that because they use acrylic that was too thin. They have since update their process. I bet the top is bowing too and that center brace is bowing downwards being pulled down because of the stress of the front and back panels pulling out.

sabodish · #17 09/28/2006, 09:58 AM

i say underbuilt as well..my new 36x36x30 cube is built with 3/4" acrylic all the way around and its eurobraced.

Sara B · #18 09/28/2006, 01:39 PM

I contacted the previous owner and I guess it was already bowing for him as well. I am new to Acrylic and was not aware that I was to look at the tank for this sort of an issue when purchasing a used tank. He also said he had contacted Clarity Plus about the bowing and they said it's not an issue.

Should I believe Clarity Plus that it's not an issue or start shopping for a replacement tank?

Sara

sabodish · #19 09/28/2006, 01:54 PM

depends..will clarity put it in writing that when your tank pops they will replace everything it damages?

as much as you dont wanna hear it, id start looking for a new tank or find a way to brace your current one.

UCanDoIt · #20 09/28/2006, 02:41 PM

Quote:

Originally posted by Sara B
I contacted the previous owner and I guess it was already bowing for him as well. I am new to Acrylic and was not aware that I was to look at the tank for this sort of an issue when purchasing a used tank. He also said he had contacted Clarity Plus about the bowing and they said it's not an issue.

Should I believe Clarity Plus that it's not an issue or start shopping for a replacement tank?

Sara

It's probably not an issue as TruVu tanks use to do the same because the acrylic they used was too thin. They have since change. I remember having a couple of 40g TruVu, the front was so stretch that you actually couldn't see through it clearly, distorted. If the seams were stealed correctly, no problem, just ugly!

sabodish · #21 09/28/2006, 03:08 PM

damn....didnt know you bought a bowfront huh?..lol

wuelfman · #22 09/28/2006, 05:10 PM

my tank is 72x30dx24h it is 3/4 acrylic and there is NO bowing at all with my tank.i do know that some of the thinner acrylic will bow. that would scare me bowing like that.

bryanth73 · #23 09/28/2006, 06:30 PM

3/4 on the tank is the way to go the bow will stress the seams eventually causing them to craze and fail. Just how long is anyones guess. My 180 is a clarity tank and is only 3/8 it also deflects pretty good as well, I am in the process of replacing it as well

Sara B · #24 09/28/2006, 08:19 PM

sabodish - that's funny! I already have a 92 gallon corner tank and the bow in that tank makes things a little distorted. I was looking forward to a flat tank again ... NOT!

I am going to refill the tank again this weekend to take photo's to share with Clarity Plus and see what they say about it ... and get it in writing as well.

sabodish · #25 09/28/2006, 09:15 PM

im guessing they wont give you anything in writing. your best bet would be to try and build some type of brace for the top of the tank.