5 Gallon bucket Root Zone Water level

So i have been growing DWC for a while but i have mostly grown RDWC, but now not having a water pump and just an airstone i am wondering about how high the water level should be i have read the latest issue of cannatalk and i understand the rootzone well but just not with bud plants so what would you perfer as far as water level

Ive got water up to about 2" From the pot..

I put three gallons of water in my buckets when mixed with nutes and 3 1/2 when flushing but by the time I get them in a bucket they already have some roots hanging.

A trick I use in my buckets (loews or home depot standard buckets) is that I mark every inch and a half (1 1/2) up the bucket from the bottom for 10 1/2 inches with a sharpie. I do this because every 3 inches is a gallon of water. It makes measuring the water easier I can just grab the hose and fill to the line

I like the idea of marking the water level to quickly fill to the correct level. right now i have about 3 gallons of water in my buckets. Antoher question if i was to fill up the bucket about 2 inches from the top instead of halfway do you think it will increase growth rate

I have never heard of there being a correlation between water level and growth rate. No matter what you only have the bottom half of the 5 gallon bucket for downward root growth. So the size of your plants will be limited.

I check the water in my DWC every morning for PPM and PH with the lines in the bucket I can also get a good of how much water she is drinking.

My question is if you fill to 2 inches below how do you measure that amount of water and how much nutes do you add?

For example I use GH flora series it tells me what to add per gallon so I just x3 for the 3 gallons.