Isnt the Kratky method where you just use a static medium and the plant creates the air gap by using the nutrient solution?
Yes exactly. No need for air airstone. You will get some minor root rot as the plant gets older but it should have enough "air roots" to get the job done. Here's what my podding plants roots look like. Notice a little brown in there but not enough to affect growth.
This plant sucks down about half a solo cup per day!
Still growing. I haven't changed the nutrients
When they are young like that you shouldn't have to change them for a while. Only if it starts yellow or curl. But for the most part I don't ever change the nurtients. Just top off with new solution. Looking good!