Vodka dosing question

[daplatapus]

SO I've been vodka dosing my system with approximately 150 gal net water volume for about 3 weeks. Up to now I've been dosing in the morning before I leave for work and I'm just finishing the week of 2.2 ml and about to jump up another .5 ml.
My question for those that have done this before: Is there a point where you'd split the dose to twice a day? Or is dosing it all at once better?