Hey Growan, looking at the photos, they need some N and they even looked overwatered. Which shouldn't happen in a 2L perlite hempy. I can't say I know anything about Dyna-Gro Grow, or Mag-Pro Protekt. But as small as your plants are they shouldn't need to be watered any more than once a day. Should be more like every 2 days instead of twice a day. All you need to grow hydro is an NPK with a full set of micros and some free cal to aid in nute absorption.
My first thought would be to pick a water source, rain has little to no minerals, and needs cal/mag, silica, & other basic minerals, your tap on the other hand depending upon your location (living over limestone) may have these minerals. Figure out your water first and it will make adjusting much easier.
I mix my water 50/50 RO & tap and have done so for yrs. My tap has no cal but has a lot of silica. (Had to learn about the silica the hard way)
So in closing I'd say Pick a water, one, the other or a blend. Stick with it. Let em' dry out, and give them some N.
Be patience, and all the best, Watts