According to the instructions...
Medium- to High-nutrient Systems: Add 5 ml (1 capful) per 50 US-gallons (189.3 L) [˜2 drops per gallon (3.8 L)] of aquarium water daily. Monitor concentrations of phosphate and nitrate with accurate test kits; phosphate and nitrate should eventually become immeasurable (or nearly so) when a balance is reached between the rates of nutrient-input and nutrient-assimilation. Thereafter, switch to “low-nutrient†dosage (below).
Low-nutrient Systems: Add 5 ml (1 capful) per 100 US-gallons (378.5 L) [˜1 drop per gallon (3.8 L)] of aquarium water daily. With time, hobbyists may determine that decreasing the dosage and/or dosing frequency by up to 50% sufficiently maintains a low-nutrient environment. During changes in biological filtration or when increasing the aquarium bioload, dose 1 drop per 50 US-gallons daily for one week, then resume “low-nutrient†dosage.
5ml for 50g is probably a comparable vodka dosage.... If you are looking for a more concentrated source of organic carbon, ZeoStart2 is much more concentrated.... Most of the people are dosing .2ml per 100g......
Different organic carbon forms may be more usable than others.... But I can buy a lot more organic carbon in the form of vodka for cheaper than this. I'm sure though its a quality product Brightwell seems to be doing things right...