*making a few assumptions* If we assume you have three plants and you mix up a 4 litre container of Grow, Bloom and Micro and feed about 500 ml to each plant every two days that is 1750 ml of mixed nutrient water you will use per week. (2.5 feeding days x 500 ml dose)
As the plants get larger and feed heavier and assuming you stay in a 5 gal container, you will use 1 -2 litre of the mixture per week (at least in the beginning). In the later weeks as the plants grow larger you might add 1 litre per plant at a time but it's simple to calculate the increase needed.
Since you're only adding a few ml per litre of each of the three parts, a 1 litre bottle of each should be more than enough to feed the entire crop.
If you go to our Feeding Calculator (choose Diablo Master) it will calculate the amounts for you.