explain somehting: how does the NPK not get out of whack? it seems like you'd have too much N at some point and too little P etc. as the plant goes thru it's flower cycle.
I just make sure that there's some of everything in there so the plant can take what it needs. People grow decent plants using 20-20-20 dry ferts and you can bet that's not perfect but there is enough of everything so the plants grow fine. Things like N deficiency show up so fast it's easy to correct for it. I just kind of mentally adjust what I give them knowing what they will need according to their stage of growth. For a nOOb it probably won't work so good but I grew my first buds in 1978 and as an avid reader and grower I've learned a hell of a lot since then.
Almost every grow I do has some level of experimentation going on and from each I learn a little more. Reading and participating in the forums adds to that. The last couple of grows including this one I've been experimenting with using a 50/50 mix of ProMix HP that has no nutes and ProMix potting soil or their Veg and Herb mix that has quite a bit of organic nutes. Feeding with AN 2 - part and 3 - part nutes Works OK but no where's near the yields I have always got with DWC so the plan now is to build two RDWC setups this fall to have one on each side of a 4x8 grow space that will be used strictly for flowering. One side will have nutes appropriate for early flowering and the stretch while the other side will be using later flowering nute mixes. My current grow room will be used to veg the plants for transfer to the flowering room.
One thing I can say with certainty is there is no good reason to change nutes every freakin week for the first month or more after putting clones in hydro. They barely eat anything at first so all you accomplish is making whoever is selling the nures richer. As they get bigger and the ppm drops or you want to raise the ppm just measure out smaller amounts of nutes in the same ratio you would use for a new batch and add that to your pail/tub/reservoir until your target ppm is reached.
For any nOObs just starting in hydro get the pH Perfect nutes and use RO water for a care-free grow. The base nutes aren't going to cost much if any more than GH and you won't be making Miracle-Gro/Mon$anto richer. A liter each of the 3 - part will grow you a couple pounds of pot at least for around $60. I recently bought the 4L jugs of each for $120 for all 3. Rhino Skin for silica and Big Bud are the only two supplements from AN I use. I do want to try their Bud Factor X tho as a couple bigger growers I know swear by it. Any old CalMag will do and you need very little of that. Some epsom salts once in a while and in late flowering will supply some extra S and Mg for pennies.