If I use a calculator and input 50% nicotine, it still makes me do a mix of 100% combined between the pg & vg. It doesn't matter what I try I always end up with a negative number for the pg (that's what I'm trying to use less of. I typically do a 70/30 mix). What am I doing wrong? Do I need a special calculator? I'm hoping someone can help me.

I'm completely new to making ejuice with salt nicotine, any advice on calculations would be helpful. Thank you.