The rectangle pot has loads of holes in the bottom, obviously fill the res to just below the bottom of the pot, drip feed circulates the water down so hits the roots. Althoygg once the roots are established 50% people say to lost the drip feed as not needed. They call it a brummie bubbler i believe mate last couple i done really well. Just not sure wether to start again. Does it matter if i veg for longer to give them time to grow?
For my DWC I never used top feed. When I put the clones in the pots with the balls I would use a turkey baster to suck up som of the nutes from the tub and squirt it down the pot to keep the roots moist for a couple days until roots came out of the net pots then no more top feed ever. No pumps or stuff in the tubs either like
@PhatNuggz shows. Just 2 - 12" aquarium airstones to bubble lots of air in the tubs.
Those are the net pots. 5" ones there.
An experiment I did mixing some ProMix soilless with the balls to sprout seeds right in the pots and grow 12 plants SoG style. Worked out not bad. Note the extra hole for adding water, taking samples etc. Just rented a hole saw from the tool place in town to cut holes for the 3.5" net pots used in that lid. The lid is sitting on an empty tub so I could pour water thru to wash out any loose ProMix before setting it on the tub to the left.
I always start my clones or those seeds at around 300ppm/0.6EC then once they have decent leaves going and good roots in the water add small amounts of nutes to double that then raise the ppm as they get bigger and start growing fast. I would never go over 1000ppm/2.0EC unless they were heavy feeders and my humidity, (RH), was decent. At low RH the plants drink lots more water and then I might only be 0.8EC to prevent toxic salts buildup.
Root rot is easy to get going in these things so I used to use 35% food grade hydrogen peroxide twice a week to prevent it. I used 0.5ml/L each dose but if root rot is starting then 2.0ml/L and up to 4.0 daily to kill it off. I made a chiller out of an old water cooler and then no more peroxide. I could keep the nute temp to 65F - 68F and never had rot.
Good luck!