Acrylic tank cracking!

[Ron Popeil]

I have a friend with a 300 gallon acrylic aquarium, approximately 7 years old. Last year, a crack developed horizontally in the front right bracing. This crack extended downward into the front pane about 1/4 of an inch and caused periodic drips of water. We siliconed the inside and outside of the crack to keep water from leaking, aware that the structural integrity of the aquarium was compromised. The leak has stopped.

A year has passed and now another horizontal crack has developed on the top front left side bracing.

The tank needs to be replaced, but my question is why is this occurring? Why only on the front bracing and not side, rear or middle braces? The canopy is ventilated with two constantly running fans, there are five 400w halides, is this heat related? The stand is a steel frame, is even and the tank is level. Could this be related to the house settling underneath? This aquarium is on a load bearing wall on the second story of a very large home.

I am going to recommend he upgrade to glass, but would like to have my friend not run into any issues going forward.

Any ideas? Suggestions?

 

[leveldrummer]

I would say either the stand is not level or the tank was poorly built. I would not assume it is related to heat or anything else.

 

[dave.m]

I would have to second LD's suggestion. It really does sound like stress caused by being out of kilter.

Dave.M

 

[peppie]

How thick is the material??

 

[mrx66699]

I have a friend with a 300 gallon acrylic aquarium, approximately 7 years old. Last year, a crack developed horizontally in the front right bracing. This crack extended downward into the front pane about 1/4 of an inch and caused periodic drips of water. We siliconed the inside and outside of the crack to keep water from leaking, aware that the structural integrity of the aquarium was compromised. The leak has stopped.

A year has passed and now another horizontal crack has developed on the top front left side bracing.

The tank needs to be replaced, but my question is why is this occurring? Why only on the front bracing and not side, rear or middle braces? The canopy is ventilated with two constantly running fans, there are five 400w halides, is this heat related? The stand is a steel frame, is even and the tank is level. Could this be related to the house settling underneath? This aquarium is on a load bearing wall on the second story of a very large home.

I am going to recommend he upgrade to glass, but would like to have my friend not run into any issues going forward.

Any ideas? Suggestions?

First off glass is not an upgrade that's a downgrade in strength, clarity, insulation, and life expecctancy. Your dt is failing because of user errors at some point. 5 400 mh can produce a ton of heat for two small fans. Look at the position of the one that is closest to the cracking use a thermometer and check the heat level at that surface. Next see if the cracking is truly coming from the bracing and then traveling down for a stop gap till you can replace it use weld on 4 and a small square acrylic piece enough to cover the cracking by about 3 in on all sides and weld it in place over the crack. The cracking has to be coming from user errors or the builder.

Sent from my EVO using Tapatalk

 

[peppie]

It will also help the crack from getting longer if you drill a small hole at the end of the crack before you add the patches.

 

[aldiaz33]

I agree with mrx and will take it a step further...if the current tank were made of glass, it probably would have completely failed by now and your friend would have thousands of dollars worth of damage to deal with. The numbers that I typically see are that acrylic is 16 to 17 times stronger than glass so if the acrylic is failing...

What is the height of the aquarium and what thickness is the acrylic? It may have just been made out of inadequate thickness acrylic for the tank's dimensions.