300ish Acrylic Tank acrylic thickness

[silentstorm]

Hello all,

We bought our 1st home & that equals an upgrade from my current 180 gallon. I've been looking out for 300ish gallon tanks (8ft long) & lately am seeing a few of them for sale in my local forums.. But one problem... They are all acrylic tanks with 1/2" thick acrylic...!!

I've never had acrylic before but am ready to deal with the scratches etc.. While some say there will be some amount of bending, just a 1/2" thickness for a 300 (8ft by 2ft by 30" tall or 8ft by 30" by 2ft tall) doesn't run good through my mind...
I did see one tank running as well... and I saw atleast 1" deflection in the front panel.. and less than 1/2" deflection in the back panel.. The guy said its been like that for 5 yrs..!! and everytime he empties and refills (guess he does that once in a while to catch fish) he notices the bowing slowly start while filling half way..but nothing to worry cause acrylic will has some deflection.

Am really concerned.. Is 1/2" acrylic enough thickness for a 8ft long tank?? well, atleast some manufacturers thought so..!
help me piece this together... those with acrylic & subject knowledge please pour in your comments & thoughts...

While the price is right, I don't want to risk it for a few hundred savings up ahead.. But if this is normal with acrylic.. I might go forward..

Thanks for your time.

 

[dave.m]

It is not the length but the depth (height) that has the weight of the water that causes deflection, whether glass or acrylic. If the tank has at least 4" wide eurobracing around the top I would not worry too much. If the tank has no eurobracing I would be concerned. You could get stainless steel clamps made that would hold the tank square along the top but at 1/2" I would still be concerned about the bottom popping out.

Dave.M

 

[silentstorm]

Thanks for the clarification Dave.. The one I checked out currently running was 8ft by 2ft by 30" tall (always had 24" tall and I have to say, it was awesome with the extra height)... I guess at 30" tall, it would've had the max bowing... It did have full bracing on the top with 3 openings with lids. Not sure if it was 4" but looked like it.

I am checking out another one today but this one is only 24" tall ..30" deep which is good ... I guess this one might be better.. lets see.. But still I wish I find a glass one or thicker than 1/2" acrylic..

 

[dave.m]

I have had up to 36" tall glass at 1/2" Starphire glass, but it had eurobracing at both top and bottom.

Dave.M

 

[silentstorm]

I have had up to 36" tall glass at 1/2" Starphire glass, but it had eurobracing at both top and bottom.

Dave.M

Did it bow any at all with the euro bracing?

I was thinking about the plywood tanks... If i get this 30" tall tank.. and build a plywood frame around it.. I doubt if the bowing will be gone. The euro bracing in this case will add to the strength of the corners (the seams will be stronger) but will still let the bow happen.. is my thought. Please correct me if am wrong..

 

[dave.m]

No, the glass tank with eurobracing did not bow. No tank should bow, as it stretches and weakens the material of whatever your tank is made of. Nothing with eurobracing should bow.

I don't think a plywood surround would help your proposed tank's bowing situation much. That is why I suggested clamps on the top to help keep the tank's original shape. Bowing is a bad thing.

But if you're wanting to buy a used tank I would suggest you keep looking until you find something safer. If the tank you are currently looking at is five years old and has always bowed I would consider its lifespan to already be shortened.

Used tanks come up for sale all the time. Depending on how desperate the seller is you can often come away with a tremendous bargain. Just be patient and let your dream tank come to you.

Dave.M

 

[nuxx]

I'd do 3/4".

Did 1" on our 470.

 

[silentstorm]

No tank should bow..!! I like that....

So, I checked out the other 300 gallon tank yesterday.. this one is 8ft by 30" by 24" tall... it is 1/2" all around.. but 3/4" top & bottom.. Guess what... there was a slight bow...!! both front & back... almost like your eyes are playing tricks... but there was definitely some. along the front & side panel, 4" euro bracing and along the back atleast 8"..

I wonder how much safety factor the manufacturer put in...

Guess I'll go back to the waiting game...

 

[nuxx]

Almost did 3/4" starphire on our 60x36x16" frag tank. Ended up doing 1/2", glad we did... it's a beast.

I'd be nervous with anything over 8' long and 24" tall @ 1/2".

 

[foxvalleypcgeek]

My 8 foot long by 2 foot tall has 5/8 which was upgraded from the standard 1/2. Safety factor of about 3.8

 

[cdjim]

just make sure your stand is perfectly flat

 

[cabinetman123]

I build tanks all the time that size and wouldn't dream of making them outa 1/2 especially 30" tall. Mine are only 24" tall and I use 3/4. 30" tall I'd use 1"

 

[silentstorm]

Thanks for the replies ... I also feel better to wait than risk it ... too much at stake!

The 2nd tank I mentioned is a good deal...with slight bow in the front. But I am going to let it pass...
Hopefully I find something sooner... hard to keep the reef bug from taking control!! :headwally::spin2:

 

[silentstorm]

What you guys think about this tank dimension?
8ft x 4ft x 16" tall ..... I just love the 8ft & 4ft depth... but just 16" tall.. initially was thinking it'll look too shallow..but I saw it in person & its not that bad!! Center overflow too... and I would love to set it up in the middle of a room & have a walk around it... would like to hear about your opinions on the dimensions.. pro's & cons..

Few concerns... the acrylic thickness is 7/16" .. but there is no visual bowing of any sort ... I think its a Bashea tank.
Originally had a 6" euro brace and no center brace.. and has had some cracks develop in the corners of the euro bracing... and since then, they have added a 4" x 4" piece welded to all corners & also added a 6" center cross brace.
Has been this way for more than a year.

Anyone see any concerns??

 

[dave.m]

If it has started to crack you should run away. All the patch jobs in the world cannot compensate for the fact that the tank has already started to fail.

As for wide shallow tanks, the set-up you suggested is best. Looking through the side of a short tank isn't much fun, so you would want to add the ability to look down from the top.

Dave.M

 

[silentstorm]

Dave, thanks for your input..
Is crazing the same as cracks? I guess i should've been more specific... The crazing (not a full blown crack like splitting) is in the 6" euro bracing only (the tank sides are near perfect)... and like I mentioned, all the corners were reinforced with a 4x4" piece .. and center cross brace.
Let me see if I can get a pic or 2..

And as always, I'd like to discuss the facts as they are while I won't convince myself to get something just cause its a deal! can definitely wait but also dont want to miss a good dimension..

 

[dave.m]

Crazing is an indication of stress. It may hold forever. It may crack further if more stress is put on it in future, e.g. not level, uneven bed, etc.

If extra bracing has been added then the current owner has made sure to prevent the crazing from worsening. That is an indication to you that you must be even more vigilant and take precautions to keep the tank braced. If the price is still good with all these caveats and you're willing to take the risk then it may be worthwhile.

How's your house insurance?

Dave.M

 

[silentstorm]

Hmmm... I just bought a new house! Not really sure about the insurance...like to what extend they cover. On the other hand... I wouldn't want to be there either..

Well, the bracing & 4x4 pieces to each corner was added by the 1st owner & pretty much the guy who bought it was in my shoes ... he pushed it & the tanks been running for over a year..
I wonder why these manufacturers just use the minimum required material to hold it good... why cant they up the safety a bit... understand its all about the money for them... but its killing me!!!