Aquarium question

dfuze

Lifer
Feb 15, 2006
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A coworker just gave me a 20 gallon tall aquarium. I noticed that the bottom plastic frame has a hairline crack about 4" from the end. The glass and seals seem intact. On a tank this size is the plastic structural or is it ok as is?

It's currently on the back deck filled with water so I can check the seams overall, but I'm wondering long run issues.

c6e4e2e9-5ab9-d5d4.jpg
 
Sep 7, 2009
12,960
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20 gallons is a LOT of water when it's spreading over your floor and seeping through down the basement.

I'm surprised they don't have an aquarium stand that is 'spill proof' with a holding tank underneath in case of a leak.
 

BoomerD

No Lifer
Feb 26, 2006
66,345
14,752
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It's PROBABLY OK...but I'd be leery. the plastic trim does help hold the glass panes together...to a point.

I've built several aquariums from glass and silicone, so I KNOW they'll hold without the trim...MOST of the strength is in the silicone, but the plastic also helps quite a bit.
 

MWink

Diamond Member
Oct 9, 1999
3,642
1
76
I'm not 100% sure but from what I've read the plastic rims are critical to the tanks structural integrity. I would not fill a tank with a damaged rim anywhere near full. However, it might be ok as a terrarium.

Considering it is only a 20Gal it would not be that expensive to replace if you really want an aquarium (maybe ~$30) I'm sure that would be cheaper than cleaning 15-20 gallons of water off the floor. It may hold water for a while but I've read some horror stories about people using tanks with compromised rims. It's up to you if you want to take the chance.
 

dfuze

Lifer
Feb 15, 2006
11,953
0
71
As for the others, thanks for the responses, I think it is probably safer to get a new one.
 

Gooberlx2

Lifer
May 4, 2001
15,381
6
91
Can you post a better/closer pic of the crack? Depending on severity, you might consider trying to repair it with glue or silicone or just scrapping it altogether.

As mentioned, 20 gallons is a lot of water when it's all over your floor.
 

richardycc

Diamond Member
Apr 29, 2001
5,719
1
81
1gal water = ~8lbs, so 20gals = 160lbs of water sitting on the small crack...it's a disaster waiting to happen.
 

NutBucket

Lifer
Aug 30, 2000
27,154
635
126
A "normal" 20 gal tank is pretty cheap. Also, are you sure its an aquarium and not a terrarium? Not sure how one would tell once the labeling is removed.

Hell, the actual aquarium is probably the cheapest part of the setup!
 

BoomerD

No Lifer
Feb 26, 2006
66,345
14,752
146
A "normal" 20 gal tank is pretty cheap. Also, are you sure its an aquarium and not a terrarium? Not sure how one would tell once the labeling is removed.

Hell, the actual aquarium is probably the cheapest part of the setup!

No shit. Some of the local aquarium stores run "$1/gallon" tank sales on a regular basis because they know that the glass tank is the cheapest part...and once you're hooked, you'll spend more and more and more and more...........
 

dfuze

Lifer
Feb 15, 2006
11,953
0
71
I tried another pic of the plastic using my phone. I can have my wife use her SLR later tonight if you need a better shot. It's been on the deck now for about 3 hrs 90% full (just an FYI)

46bca107-78f4-0f99.jpg
 

Rubycon

Madame President
Aug 10, 2005
17,768
485
126
Modern "all glass" aquariums using RTV (silicone) sealant to bond the glass together are quite durable in small sizes. The plastic frame on the bottom is both functional and adds some pleasing aesthetic qualities. That said the crack/gap (as pictured) does not appear to be as threatening as it may seem.

OTOH what is far more stressful to a "fish tank" is placing it on a non level (i.e. not a proper stand!) surface and filling it with water! That WILL challenge the fillet/bond junctions and can cause them to be compromised so there is a leak - eventually. ALWAYS place the tank on a proper stand/structure and make sure it's as close to being level as possible.

The top frame, particularly in longer tanks; is actually more important than most think. The cross braces if so equipped are there to prevent the load from the water column from pushing the glass panes too far out of parallel. This can also result in bond/bead failures if allowed to go unchecked. NEVER cut or remove a cross section brace on the top to afford better lighting (shadow reduction) as this will almost guarantee a problem!
 
Aug 26, 2004
14,685
1
76
Modern "all glass" aquariums using RTV (silicone) sealant to bond the glass together are quite durable in small sizes. The plastic frame on the bottom is both functional and adds some pleasing aesthetic qualities. That said the crack/gap (as pictured) does not appear to be as threatening as it may seem.

OTOH what is far more stressful to a "fish tank" is placing it on a non level (i.e. not a proper stand!) surface and filling it with water! That WILL challenge the fillet/bond junctions and can cause them to be compromised so there is a leak - eventually. ALWAYS place the tank on a proper stand/structure and make sure it's as close to being level as possible.

The top frame, particularly in longer tanks; is actually more important than most think. The cross braces if so equipped are there to prevent the load from the water column from pushing the glass panes too far out of parallel. This can also result in bond/bead failures if allowed to go unchecked. NEVER cut or remove a cross section brace on the top to afford better lighting (shadow reduction) as this will almost guarantee a problem!

Not to sound like a typical ATOT leg-humper...but is there anything you don't know something about? :)
 

Rubycon

Madame President
Aug 10, 2005
17,768
485
126
Not to sound like a typical ATOT leg-humper...but is there anything you don't know something about? :)

Yes of course!

If I were to put a number on everything I know of three, the number on everything I don't know would have at least ten digits. ;)

p.s. Dogs cannot ask so they just go ahead with it. Never hurts to ask first before, you know... :D
 

NutBucket

Lifer
Aug 30, 2000
27,154
635
126
The top frame, particularly in longer tanks; is actually more important than most think. The cross braces if so equipped are there to prevent the load from the water column from pushing the glass panes too far out of parallel. This can also result in bond/bead failures if allowed to go unchecked. NEVER cut or remove a cross section brace on the top to afford better lighting (shadow reduction) as this will almost guarantee a problem!
Having never had an acrylic tank before, I wasn't expecting it to deform so much and I've only got a 29 gallon!
 

darkewaffle

Diamond Member
Oct 7, 2005
8,152
1
81
That 'crack' seems more like a 'seam' where the plastic wrapped around and 'met' but IANAPE (plastics expert).
 

BladeVenom

Lifer
Jun 2, 2005
13,365
16
0
I didn't think it was important for strength. I thought it was more for protection.

Can't you just buy a new plastic frame?
 

dfuze

Lifer
Feb 15, 2006
11,953
0
71
That 'crack' seems more like a 'seam' where the plastic wrapped around and 'met' but IANAPE (plastics expert).

I think if it were a seam the top would have a similar one.

I wonder if it could be repaired, like a plastic "weld". If not, I could aways use it for a partial land/water tank (forget the term, something like vivarium)
 

trmiv

Lifer
Oct 10, 1999
14,670
18
81
Yes the plastic rims, especially the bottom rim is part of the strength of the tank. Notice the tank actually sits on the plastic rim and not the glass.

The second pic definitely makes it look like a seam. Although I can't say I've ever seen a 20 gallon tank with a seam. I just double-checked the two I have here and neither have seams, the plastic is all one piece. I don't even see a seam on my 65, but my 60 cube does have joined seams in the corners.
 

BoomerD

No Lifer
Feb 26, 2006
66,345
14,752
146
It MIGHT be possible to repair the crack with the appropriate adhesive.

I don't know which one to recommend though...different plastics, different glues.