Where do you find the courage...

[HawaiianReef]

My first cuts I went fast to get used to the cutting ability and had chipping.
Next cut I went slow and it killed the bit with grit grinding away in the cut-way (is that a term?)

The cut-way, if your talking about the notches on the circumference of the cutting edge of the bit, I think those are flutes.

 

[Greg P]

I was trying to reference the 'slot' which is created by the what you are calling 'flutes', yet a diamond bit has no flutes ... just a continuous cutting surface.
It's not coming to mind right now.
The 'slot' or 'trough' or something ... OMG someone help me here I can't find the word ... ;Woot

 

[Greg P]

Anyway, for the OP, run water while you're cutting your hole to wash away all the 'grit' to save your hole saw from wearing out too quickly. That was my problem, even though I'd cut numerous holes to start with.
Nervous about breaking the tank and wore out my bit ...