I'm late af but whatever. I use a solar panel hooked up to a 12v car battery and a small eletric water pump from a trailer. I have it on a timer to pump water to a 200 gal resuvoir once every morning from a river . Then I rigged up a water timer valve to the base of the resuvoir then run 1/2in...
Meracle grow isn't very good for cannibis plants as they use "time release" nutes in their soil and cannibis is an annual plant mostly so it's better to have a soil that has all the nutes avalible to the plants faster.
Your lil plant looks like it's over watered a bit and possible nute burn.