Testing glass tanks for drilling

[Fishko]

just wanted to share that the ti-84 plus ce calculators have an lcd display and can be used to test if a tank is tempered. I was a little wierded out by bringing a laptop to petco. I bought a 75 by accident a few years ago and found out it was tempered.

 

[redfishbluefish]

All you need is a phone and a pair of polarized sunglasses.

 

[Fishko]

All you need is a phone and a pair of polarized sunglasses.

I tried it with my phone i didnt see it at first it was really subtle