Share 'Low string'

I'm up to my 10th CBG, I've been satisfied with the results for the most part. I seem to be having a problem tuning the low string. I've broke several strings trying to get the G tuned in. Don't know if it's a problem with my build or what. Any suggestions would be appreciated. I'm using a digital tuner I purchased from Gitty, and have also used two different tuner apps that I have on my iPhone.