roots yellow/brown

hey guys need help again i changed my res water out yesterday added nutes and today the roots are yellow mabey light brown only up to the water level the top parts that are not in the water are perfecly white still the ph is the ppm is only 187 and the roots are about 18 inches the plants are 9 to 12 inches today also cant stop the leave tips from drying out dont think it could be nute burn with a ppm of 187 at this size of plant the water temp stays around 69-72 degrees the light is now 3 feet 9 inches away 400w hps i had root rot before on some white widow and these roots arent slimey like those were could the nutes have just colored the roots i need to know before its to late can post pics if needed thanks guys j420mankiss-ass

What kind of system is it? I'm assuming dwc from your explanation, nutes can have an effect on root color so if it looks like your nutes I would just stick with it, but if the water temp is over 70f than your asking for the rot I would definately lower the water temp to maintain below 70 even below 65 if possible just to make sure. Also there are lots of enzyme products on the market and if your in dwc i believe its worth the investment it helps protect the roots, cannazyme, multizyme somewhere in those lines. By the way don't be afraid to lower the water level a lil, i dont know what its at now but a couple 2-3 inches below the netpot is fine as long as you have some roots still touching the water, the humidity inside the buckets should keep your exposed roots nice and moist. Maybe look into getting that light closer and raising those ppm's too a plant that big needs food the poor ladies are probably starved. Good luck!

cool thanks man i'll trythat i know the light needs to be closer but the tips keep turnind brown i keep thinking its nute burn or light burn when its not

and yes it is dwc =)