The plants look very nice but I've got some concerns about how you are watering them. What size are your pots? They look to be about 3 gallon. 750 ml is less than .2 gallons. A 3 gallon pot would normally require about .75 gallon per watering. Remember you want to give enough water so that about 10% of what you give runs out the bottom of the pots. As nutrients are broken down they create a bi product, which is salt. The extra water that runs out the bottom of the pot helps to flush those salts out of the soil. Should the salts build up in the soil they can inhibit the plants ability to uptake nutrients properly and the plants will suffer. Given the size of your pots, the size of your plants and a proper watering with run off, I wouldn't expect your plants to need water more than every 6-7 days at this point in the grow. .2 gallons in that size pot isn't enough to get water down to the roots at the bottom of the pot.