Need help! 180 Acrylic developed cracks

cediss

cediss

Active member
Just now found two large cracks in top of reeftank. One crack runs from back edge of opening to overflow box, the other runs from front edge of opening at opposite side to the front corner of tank. I'm no expert but this seems to be fatal for this tank. I'm not sure what to do, but I'm thinking I need to find a new 180 today. Anyone know where to get a good quality tank at a fair price today? Any advice is appreciated!
 
drain it down to 2/3 level...use powerheads for circulation. do water changes every few days.you should be ok and will buy you time to find a tank.

Not sure where you can get one cheap,but hopefully others on here will chyme in.
 
Hey thanks to all who sent PM's as well as to those with advice on this thread.
Here's the update. My buddy Craig came by with some1/4 inch acrylic and we welded this onto the tank with acrylic cement over the cracks. These braces not only cover the cracks but go from the front to the back of the tank. He has worked with acrylic a fair amount and he thinks it will hold. Mainly because the front and side panels of the tank have no bowing, the joints are nearly flawless on the tank, and the acrylic is 1/2."
I hope this works, but if there is any evidence that it wont work I'm gonna have to buy a new tank. Thanks again to those who pointed me in the direction as to where to get the tank.
Any other advice is still appreciated!
 
Any idea why the tank cracked in the first place? From your sig, it appears to be a relatively new tank.
 
glaudds- Good question! The working theory is that the heat from my 400 watt halides caused the acrylic to weaken over time, until the pressure caused it to crack. Other than that it cracked at the weakest points. Where the cut outs in the top formed a thin brace. Once that section went it caused the second weakest point to crack.

IsaaX- I don't know. There is no label on it. Which could be the problem, however, the quality seems to be pretty good. The seams are free of any air bubbles, it's 1/2" acrylic, and all panels are bow free except the top. So the only thing I could say negative about this unknown manufacturer is that perhaps the cut-outs should have been placed better or smaller. But that being said, the cut outs are fairly standard from what I've seen.
 
Do you think your tank stand is perfectly flat? I'm not sure if any pressure points will cause the top bracing to fracture, however. Something to rule out.
 
what are the tank dimensions?any tank over 4ft long and 20"tall should be minimum 3/4"thick.that tank is underbuilt and thats most likely why it cracked.
 
<a href=showthread.php?s=&postid=9933405#post9933405 target=_blank>Originally posted</a> by checkinhawk
what are the tank dimensions?any tank over 4ft long and 20"tall should be minimum 3/4"thick.that tank is underbuilt and thats most likely why it cracked.
Click to expand...

Umm.. totally inaccurate. 1/2" is fine for a tank this size, being that the top is adaquately braced.

To me sounds like your lights we the cause of the crack. If they were heating up the acrylic, then you would see cracks in the top. More than likely your openings were just a bit too small for that size light. Sounds like the tank was built properly, based upon what you've told us, so you might want to be sure that your lighting doesn't heat up the top bracing to avoid any further damage on this tank or a new tank. HTH.
 
yeah for a tank that size 1/2 inch is good up to 24 inch in height. agter you go to 30 inch then you need to go 3/4 but other wise its ok. Oh and also if you do a euro brace on a tank with a 24 inch height then yeah it would need 3/4 but in this case 1/2 is ok. Are you lights aimed right over the access holes. Because with 400w MH its good to have them on a 24 inch height tank at about 10 inches off the water surface.
 
i had a 135 & 180 gallon seaclear tank break just like that...both in the same spot...both had metal halide lighting...with no openings in the canopy for fans...thats what had to have happened...mine had cold water in the tank because of the chiller...and really hot acrylic on top with no openings...luckily mine were replaced through warranty & i upgraded everytime...you dont know who made your tank huh???
 
<a href=showthread.php?s=&postid=9933438#post9933438 target=_blank>Originally posted</a> by lakersfan0014
Umm.. totally inaccurate. 1/2" is fine for a tank this size, being that the top is adaquately braced.

To me sounds like your lights we the cause of the crack. If they were heating up the acrylic, then you would see cracks in the top. More than likely your openings were just a bit too small for that size light. Sounds like the tank was built properly, based upon what you've told us, so you might want to be sure that your lighting doesn't heat up the top bracing to avoid any further damage on this tank or a new tank. HTH.
Click to expand...

i have a cyro tank calculator.if that tank is over 4'long and 20"or more tall it is under built.bottom line minimum 3/4"
i just inputed some numbers into the calculator.for a tank 72"long 24"tall eurobraced it called for 1"thick.underbuilt.
download the calculator and see for yourself http://cyro.custhelp.com/cgi-bin/cy...nMuc2VhcmNoX25sJnBfcGFnZT0x&p_li=&p_topview=1
 
Last edited:
Underbuilt it may be, but it is common to see 1/2" for this size tank. I am pretty certain that the 400 watt halides that are approximately 6-8" from the acrylic did the deed. They are mostly over the opening but a portion of the bulb overhangs were I believe the crack originated. For now I will avoid using the 400 watt lights until I can come up with a practical solution to the problem.
The bracing that we glued in seems to be solving the problem structurally and I am running my 175 halides for now. These put off a fraction of the heat that the 400's put off. I wish I had perceived this problem developing, but I figured if the acrylic wasn't melting it was o.k. Big mistake. I bought acrylic over glass for safety/security, but even acrylic is not a perfect solution. Hopefuly this tank will hold up from here out. If I have to replace it I might consider going starfire, but with glass I worry about the seems more than anything.

Thanks again for all the advice and opinions!
 
<a href=showthread.php?s=&postid=9934458#post9934458 target=_blank>Originally posted</a> by checkinhawk
i have a cyro tank calculator.if that tank is over 4'long and 20"or more tall it is under built.bottom line minimum 3/4"
i just inputed some numbers into the calculator.for a tank 72"long 24"tall eurobraced it called for 1"thick.underbuilt.
download the calculator and see for yourself http://cyro.custhelp.com/cgi-bin/cy...nMuc2VhcmNoX25sJnBfcGFnZT0x&p_li=&p_topview=1
Click to expand...

That Cyro calculator is flawed, and many acrylic aquarium fabricators will not use it. Like I stated before if the tank is adequately braced 1/2" is fine, of course theres nothing wrong with overbuilding with 3/4", as it would allow either a eurobrace or very large openings with standard cross bracing.

Cediss, glass might be an option for you, or a custom acrylic tank where the opening sizes can be determined for your lighting. I do think that 400 watters are a bit overkill for a tank that size, but if you were to keep them cooled by fans, and have a large enough opening, you would be fine. Just a thought.
 
1000 watt halides don't melt glass.......................doesn't matter what kind of bracing is on top.. ;)

Maybe heavier but the goods outweigh the bad IMO
 
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