You can start with 0.1 mL/100 L for the first three days.
Then you increase the vodka volume to 0.2 mL/100 L for day 4-7.
Subsequently to this initial week you increase the vodka dose by 0.5 mL per total tank volume (this is important, do not dose on a per 100L basis, but on the total tank volume!) every week.
So, e.g. for a 500 L tank:
day 1-3: 0.1 * 5 = 0.5 mL
day 4-7: 0.2 * 5 = 1 mL
2. week (day 8-14): 1 mL + 0.5 mL = 1.5 mL
3. week: 1.5 mL + 0.5 mL = 2 mL.
After these 3 weeks you should recognize changes in the nutrient levels (nitrate, phosphate). If the nutrient levels are still unchanged, you should further increase the dose by 0.5 mL per total tank volume.
As soon as you recognize either nitrate or phosphate to start dropping you shouldn't further increase the vodka volume but watch the nutrient levels, even in the first three weeks.