reservoir water level question !

[Silver Balls]

I'm setting up a closet grow system with 5 gallon buckets and I'm using 6" pots suspended through the lid of each bucket. I plan on using floral foam for root support. How far up inside the bucket should the water/nutes be with the pots installed? :rasta:

[Gen]

Just below the pot line, if you're doing a bubbler.