First Hydro Set up - Curling and spots

So I'm doing my first hydro grow, and I'm about 3 weeks in. One of my plants started having these spots on them about 2 weeks in. I hoped it would go away, but it hasn't and more are being affected.

I'm using half-strength "General Hydroponics Floralicious Grow 1-0.7-0.6" Specifically 1 tsp per 2galls.

See pics attached. Please help :'(

EDIT: 2 Reservoirs, 4 plants in each. 3 are shown below, 2 the spots are barely noticeable, the other 3 are perfectly healthy. PH is 5.5-6.0

get you some general hydro flora micro nutes.they work great.i use the flora grow,micro,and bloom and its perfect.

make sure your solution is clean?