Please help FEEDING CYCLES FOR bubble ponics

I have airstones and feeding tubes attached to each rockwool cube.
How often do I turn water pump on and how long when roots are and aren't submerged in the resevoir.

i go 3 times a day
15mins per cycle
in the light stage and go as much as 5 a dat when they are big

i hear that some 24 7 until roots touch resevoir do youthink this would cause water logging

yeah stealth bubbleponics do that and they use a small starter block that would not hold as much moisture so the pump works well
i used a small pump on all day and it worked good
but if ya bulk up on the rockwool and drip feed it ,it works just as well and i find it easier than checking water heights
i use two layers of r/wool so by the time the plant show roots she a big one anyway then she hits the bottom and boom "superplant"