glass hole drilling

[nilesh7318]

I am building an diy aquarium i have ordered glass. i had a hole drilled on the glass for overflow (on side glass of aquarium). the glass is 10 mm thick and the drilled hole is 10 mm in diameter. but since the glass is tempered the glass workers have have made a linear cut to the hole. this straight cut as they have said is to relieve the stress of tempering. Is this straight cut acceptable for my fish tank. the photo shows the glass with the hole.

 

[nilesh7318]

the hole is 10 mm dia and around 1 inch from both edges of glass and it is on the side glass of the aquarium. aquarium capacity is 240 liters. the straight cut is running to top of the glass