Advice on Monster 1400 gallon used Acrylic aquarium

fuelman

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Appreciate all of the input guys, I have been leaning away from taking this on as many of you have suggested, but dang do I want it :) I may see if he'll drop the price to the point it would make sense to cut it down.

Could anyone provide input on what would the an appropriate height for this thickness of acrylic?
keep in mind that cutting down a tank with a 3" bow is not gonna be fun. the tank is deformed in the middle from bowing outward, when you cut it you will have the new top of the tank right in the middle of that bow. so unlike a new tank that's square on all four sides, this tank will be curved along the display panels because of the bowing. trying to cut a double curved top panel to match the bow in the front & back panels of the tank??? not really ideal. trying to cut a square top panel & then clamp/compress the display panels back to being square & install the top panel??? not as easy as it sounds. just a few things to think about that i learned the hard way.
 

SoggyNW

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I'll join in with the 30" cut-it-down crowd...

120 x 52 x 30 would be an epic tank...

And it's an EASY mod for an acrylic shop. Just cut straight and level and finish it with a router and join new top bracing

Also... if they cut the top off neatly, they could finish the scrap into a 120 x 52 x 20" (frag) tank itself with a new bottom and top brace
At only 20" tall I wonder if he would even need a top brace. Actually if it were me and it was a frag tank or lagoon I think I would under fill it to avoid needing any bracing.
 

Jon Warner

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At only 20" tall I wonder if he would even need a top brace. Actually if it were me and it was a frag tank or lagoon I think I would under fill it to avoid needing any bracing.
Yeah, for a tank made from scraps it's be great for frags. And it wouldn't need a full top brace. Maybe corner braces and a few across the width? Two tanks for one!!
 

ca1ore

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I’m certainly no acrylic tank building expert, but a few things don’t really pass the common sense test for me. First is that the cracks look like mechanical stress not a result of heat stress where you’d see some discoloration. Second, hard to see how an eurobraced tank like that could even bow 3”. That’s a HUGE amount. Perhaps the seller meant a 3” bulge in the center of the long axis. But even that strains credulity frankly. I’d think the tank would have completely destroyed itself. At the very least you’d see some pretty extreme crazing. Third, regardless whether the bow is hyperbole or not, 1 1/4” seems way too thin for 52” tall. Agree that 2” is probably required.

Not sure that an acrylic tank ‘holds’ the bow once empty. Pictures certainly don’t indicate that to be the case. Perhaps somebody who actually knows acrylic could comment.

These things usually come down to $$. If the seller is fire saleing the tank then it might be worth a flyer and try to cut it down. I would not pay more than $500 for something like that.
 
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Pandashark

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keep in mind that cutting down a tank with a 3" bow is not gonna be fun. the tank is deformed in the middle from bowing outward, when you cut it you will have the new top of the tank right in the middle of that bow. so unlike a new tank that's square on all four sides, this tank will be curved along the display panels because of the bowing. trying to cut a double curved top panel to match the bow in the front & back panels of the tank??? not really ideal. trying to cut a square top panel & then clamp/compress the display panels back to being square & install the top panel??? not as easy as it sounds. just a few things to think about that i learned the hard way.

I’m certainly no acrylic tank building expert, but a few things don’t really pass the common sense test for me. First is that the cracks look like mechanical stress not a result of heat stress where you’d see some discoloration. Second, hard to see how an eurobraced tank like that could even bow 3”. That’s a HUGE amount. Perhaps the seller meant a 3” bulge in the center of the long axis. But even that strains credulity frankly. I’d think the tank would have completely destroyed itself. At the very least you’d see some pretty extreme crazing. Third, regardless whether the bow is hyperbole or not, 1 1/4” seems way to thin for 52” tall. Agree that 2” is probably required.

Not sure that an acrylic tanks ‘holds’ the bow once empty. Pictures certainly don’t indicate that to be the case. Perhaps somebody who actually knows acrylic could comment.

These things usually come down to $$. If the seller is fire saleing the tank then it might be worth a flyer and try to cut it down. I would not pay more than $500 for something like that.
Thanks for the input guys. Ca1ore you're correct the bow does not exist while it's empty, it seems straight to me although I confess I did not look down the long axis looking for that specifically. But I certainly didn't notice any bow while dry.

I don't see almost any crazing whatsoever, and the corner joints are *chefs kiss* SO clear they look new, which was nice to see.

I appreciate your point abaout the mechanical stress, there's definitely no discoloration at all.

I'm thinking about asking him if we can repair the top in his garage and fill it, so I can see what we're actually dealing with. He claims that the prior owner ran it with the cracks and the bow for several years before taking it down.

I'd definitely be open to having it cut (I'm adventurous but don't think I could handle that myself..) although I really was looking forward to sculpting a shelf at about 35" high so that I could swim the length of it underneath it all... :)
 
Top Shelf Aquatics

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The optimum height for that footprint and 1.25” material is around 36-38”. The top can be machined off and a new panel could be bonded on. I disagree with many that said the top cracks are it from MH’s. The metal halides heat cycled the acrylic, and since the portholes have sharp radius corners, which are the stress risers, eventually gave way. I have been building tanks for almost 3 decades, and can and have repaired tanks like this many times. It’s not that bad, but the bill could be substantal. I’d walk away. My work can be seen on Instagram and FB under Clear Fabrications.
 
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Pandashark

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The optimum height for that footprint and 1.25” material is around 36-38”. The top can be machined off and a new panel could be bonded on. I disagree with many that said the top cracks are it from MH’s. The metal halides heat cycled the acrylic, and since the portholes have sharp radius corners, which are the stress risers, eventually gave way. I have been building tanks for almost 3 decades, and can and have repaired tanks like this many times. It’s not that bad, but the bill could be substantal. I’d walk away. My work can be seen on Instagram and FB under Clear Fabrications.
Thanks so much for your insight!
 

Not_Eeyore

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Lots of good fixes for the outside of the box...what about one inside?
Fully granted... Much smaller tanks and much smaller bows.
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The arch will always be the strongest brace known to man.
 
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