I grow simple. I use MG "Expand N Gro" mixed with about 30% vermiculite. That is perfect from veg through to end of flower, easily. Now and again I give them my nutrient tea* as a treat. Rest of the time, just plain old water.
* - 2 litre bottle, filled 1/6th full of dry expand n gro, drop in a basic mineral multivitamin, fill the bottle with warm-almost hot water. Put the lid on, shake that puppy, do the hula, pump that daddy, whatever, then let it sit/cool overnight. Applied to plants in place of just water from time to time. In flowering, I'll sometimes put a diluted dose of blossom blaster (phosphorous) in the tea as well, thats how I apply the higher phosphorous. All GENTLY, avoiding any extremes of anything.
I've had no significant nute problems, and certainly haven't used any 'designer' nutes. A note on the vitamin pill, the most basic the better, an all rounder high in minerals is good. In its dissolved state it is available to the plants/soil. The less colourings/unnecessary crap the better (thus cheaper tends to be better than expensive). This is just to ensure certain grounds are covered - gently. Better to have access to all, than an overabundance of any.
So many people get into the habit of giving the plants this, that and everything in between. They're like super overprotective parents, thinking their kid isn't getting enough and force feeding them everything, in turn the kid gets sick, but the intentions were well etc. Good intentions pave the road to hell here.