NAD+ buffered and crystalization

[xo0firefly0ox]

I recently reconstituted my 500mg vial of NAD+ buffered with 3ml but less than 2 weeks later, it crystalized. I left it out of the fridge as told to by the company to see if it did anything with the crystals which it did not. The company was awesome and sent me a replacement but I'm now afraid to reconstitute it in fear of crystals forming again. I keep all my vials in a storage container in my fridge and other peptides seem to do just fine and I've only had issues with NAD. Should I be reconstituting with less bac water?