Hey there MrMunchies! In the beginning start with the water an inch, inch and half below the net pot. then once you get a decent amount of roots in the water you can drop it an inch or 2. that will encourage some more downward root growth. once you have a ton of roots in there you can keep dropping the water down if you want little by little until your desired level. You can also drop it a little in the beginning then once you have an established root ball keep the water at that level and make sure the roots are getting plenty of Dissolved oxygen and they should flourish. for example in my RDWC setup i will start out with an inch below the net pot, then once they have a good amount of roots about 2-3 inches in the water that's when I lower it another inch or 2 and after that i don't lower it any more the max I lower it from the net pot is 5 inches and have been getting great results. just make sure you have plenty of oxygen in there! Happy Growing!!👍