View Full Version : Glass or Acrylic Sump? Pros and Cons

10/17/2007, 10:16 AM
I have been taking a lot of heat lately from my local reef club.

I built a sump out of a 20g tall glass tank. Added baffles, drilled it for the return pumps, painted it. I had it running with fresh water for over a week. I went ahead and put everything together, added saltwater, 1hr later...CRACK!
Tossed that one out, got a 20g long glass tank. Went through the same process. NO DRILLING! I guess that when I measured the stand, I misjudged by 1/4"...I tried to put it under the tank...CRACK!

I finally decided to enclose the entire inside of the stand...In GLASS.
I used 1/4" thick glass, and Dow 999a silicone.

The question...

What are the benefits of BOTH...Glass and Acrylic?
What are the drawbacks of BOTH...?

10/17/2007, 10:42 AM
Does anyone see anything wrong with this?

Compared to acrylic, is this dangerous?


10/17/2007, 01:16 PM
No matter how well built a stand is, the properties of wood will change... especially in a moist environment. The result may occur only weeks, or months after you have your sump filled with water. A minor change in the wood as a stand will not affect a tank that is sitting above, but if your tank is dependant on it as part of the structure (as in your plans)... you can get a crack, a break, or just a bad seam. I have both acrylic and glass sumps, with no bad experiences. Acrylic will allow you the flexibility to drill easily, is light weight, and not likely to ever leak under normal use.

Glass tanks are readily available and easy to use as a foundation of a sump.

As for the cracking... perhaps your baffles were more snug than they needed to be, or they were just the two tanks that were defective... I cant know... I still have two glass wet/drys, and two acrylic, with in sump skimmers.... working fine.

( I hope I don't get home to find a failure)

10/18/2007, 01:15 AM
The stand is not part of the structure of the sump. The tape you see is only to hold it in place until the silicone set up. The Dow 999a is extremely strong.
The front and back are 1/4" away from the stand. Cannot be seen in the pictures very well.

With that information....Can anyone see any reason that this would be dangerous?
I have used a 10g tank (1/8th inch glass) for over a year now without a problem.

10/18/2007, 07:19 AM
Did you build the sump in place with the main tank filled with water? If not expect the stand to settle a bit . It may not be enough to couse your seams to come apart or the glass to brake,
but I would fill the tank with water and pay attention to how the stand settles in place. That will give you an idea how the sump will behave.

10/18/2007, 04:46 PM
I'm using a Rubbermade stoage container for my sump. No chance of that cracking, and its easy to drill. And they can be found in almost any size. Might be an option if you keep having trouble with glass.