# Acrylic versus Glass tanks in Earthquake Areas; Tank Protection Measures



## fishstein (Dec 12, 2005)

I may be relocating or living part of the time in Northern California and was wondering - because the area is seismically active, do most people buy acrylic tanks instead of glass? Are there any special measures to take to protect your tank and its living inhabitants in the event of quakes?

I once bought a 150 gallon tank for young cousins in LA, and a few years later the tank shattered in a quake.


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## Newt (Apr 1, 2004)

Welcome back Fishstein.

If you purchase a tank that uses borosilicate glass then the issue isnt that critical unless the quake is dramatic and then even an acrylic tank wouldn't survive. Oceanic Systems uses this type of glass and their tanks have thicker glass than the competitors tanks. This type of glass can withstand thermal shock and deflection. I used to use it in windows on a calcium choloride solvent dessicating tank and we'd have to place teflon rope gasket on both sides and use a full frame clamp and tighten down on the clamp with lots of force so it wouldnt leak. Normal plate glass wouldn't/couldn't withstand the stress.


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## hoppycalif (Apr 7, 2005)

I have had both acrylic and glass tanks when there were earthquakes. The hazard to both is the stand/tank swaying too much and tipping over. You can't prevent that by holding on to it because you are swaying too. None of my tanks ever toppled, but one came very close, and during a very mild quake. A little water did slosh out, but not much. I didn't have an aquarium when the Loma Prieta quake hit in 1989 (I think that was the year) but no tank would have survived in my house for that one. Given what could happen during a severe quake, the loss of an aquarium is trivial.


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## orlando (Feb 14, 2007)

Man Hoppy, earthquake never crossed my mind. Scary stuff, I remember when I lived in Monterrey and we had a few quakes. Nothing big, but big enough to be scary.


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## fishstein (Dec 12, 2005)

Hi Newt and Hoppy, 

Thanks for the suggestions and the welcome back. I think it's been about 6 months or more for me. My father is still hospitalized but that was a particularly tough stretch. Newt I still have to catch up on your emails/private messages still (and a whole lot more).

I read that there are 37,000 earthquakes per year in California, although only a small fraction of those are more meaningful. Quakes that you can actually feel seem common enough that I'd imagine local hobbyists would take measures to reduce damage in the event of a quake. Using the stronger glass or acrylic is a start. A few questions:

1) Which would be better - the borosilicate glass or acrylic? I've never had an acrylic tank (never had one big enough that acrylic might have been better). Also I know acrylic scratches easily.

2) Which is more expensive at a 75 gallon, 90 gallon and 125 gallon size? Borosilicate glass or acrylic?

3) Hoppy, would bolting the back of the tank stand to the wall be at all helpful?

4) Have you ever heard of any system underneath a stand that would help reduce damage, much the way tall buildings are designed with spring, roller or pendulum systems to absorb quake energy or wind? 

It's hard for me to believe that local hobbyists or local fish stores don't take more protective measures than just going with stronger glass.


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## overboard (Mar 11, 2008)

Securing the stand to the wall wouldn't hurt, but do it with eye-bolts and straps, so there is a little give. They sell kits here for dressers and bookshelves and stuff like that. The key is to allow a little movement. It depends on the quake- if the movement is from the narrow side of the tank, it could tip in a minor quake, but if it is the length of the tank it might ride out a moderate one with just a lot of splashing. If you are moving to the Bay Area, there are too many faults to predict the direction. But Hoppy is right, if the quake is that strong, the tanks will be the last thing on your mind. Research the exact area that you are going; growing up in San Jose I felt one or two quakes a year, in six years in Sacramento I have never felt one. The liquor stores here don't even have the wires to hold the bottles on the shelves.


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## hoppycalif (Apr 7, 2005)

Earthquakes are just fun until they get really severe, like the Loma Prieta quake, which killed all interest I had in remaining in the Bay Area. Fortunately, Sacramento doesn't get quakes to speak of. Right now the Reno area is in the middle of a swarm of them - that would induce some panic if I lived there.

I think strapping the stand to the wall would help a lot. From what I experienced, as Overboard said, the effect depends on the direction of the motion. My tank, which was only a 40 gallon one, sat out in the room with only one end near a wall, and the motion was front to back. When that happens the top heavy stand/tank acts like a pendulum to amplify the motion and try to topple over. You just can't stop 300 pounds of water from falling over once it gets going good. 

Acrylic tanks cost a lot more than glass in large sizes, and they will topple over just as easily. I think the best idea is to just forget earthquakes, since anything but a minor one is very rare anyway.


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## dawntwister (Sep 29, 2007)

fishstein I have a question for you concerning lights that you used. Unable to send pm for your box is full. Would you please fix it so I can send you a pm.


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