^^ Totally right ^^
No food for first 2 weeks
In DWC you should have the air pump on always, and the water pump recirculating the res nutes every 15 min would be ok - IF thats what you meant by having the timer set for 15 min every hr.
If you are using ebb n flow, or aeroponics, then that is much too often for feeding, and you are killing them. aeroponics can be done slightly more often than ebb n flo, but not much.
Also ur plants do not have established roots systems.. so unless you are top feeding them AND spraying them for the first week, then they are not getting jack shit.