Technically you can. According to the website the 29 gallon is not tempered.
http://aqueonproducts.cvt.int.central.com/assets/011/19107.pdf However, they do have a disclaimer on their site "
Due to glass availability, Central Aquatics may temporarily substitute regular or non-tempered glass panels with tempered glass panels. Anytime a glass substitution is made, a sticker will be adhered to the aquarium bottom as a precaution to the end user.
Please Note: Any aquarium that has been altered in any way (i.e. - drilled, attempted to be drilled, the center brace removed) by an individual outside of Central Aquatics, will deem the warranty null and void. "
Best way is to check yourself with a laptop and pair of polarized sunglasses. [/QUOTE
I tried the trick, do you know if this works with green polarized glasses. They were turning purple no stripes.