g'morning sir, and welcome to the fam.

i'm growing right now in a homemade mash up between dw and rockwool uni-slab

w/ general hydroponics 6 part aggressive. (are you sure you're running 1500 ec & not

ppm?) 1500ppm is my top limit, above that tips can start burning (depending on cultivar)

1500 is imho way to high for that young of a plant, should be around 600-800 ppm.

the beauty of hydro is if things start going south, all you have to do is drain the reservoir,

clean it out & flush the shit out it for at least 1 hour w/ plain water at 5.8-62. after

that, mix a fresh batch @ 1/2 strength or around 400-600ppm for plants that size, again

imho. very important, always mix calmag in plain water first, (unless using silica, if thats

the case, silica must be added 1st,then calmag, then base, then whatever else you're

putting in it. also, it looks like your feeder tube could be closer. my plant is 40 days old

from seed. hope it helps or gives you ideas

peace