Myka's 20 gallon Zoa reef (pics Nov 15)

[mike31154]

To check if the glass you're wanting to drill is tempered, a pair of polarised sunglasses & a notebook computer (or any small LCD display screen such as a tablet, maybe even a cell phone screen) will usually do the trick. LCD screens on most of these devices are also polarised to help make them sunlight readable. Look through the glass at the LCD screen with the polarised sunglasses on and rotate the laptop. The laptop or other device you're using should have a white screen on it for this to work properly. Just open a blank page with Notepad or some other simple word processing program. As you rotate the LCD screen, if the glass is tempered you should either see a changing pattern or the screen on the other side get dimmer/brighter as you rotate it through at least 90 degrees. Hope this makes sense, if not a search will likely bring up something with a graphic example of what I'm talking about. Seen a few on other forums.