Ppm quick question

Hi all,

i read a lot of info about PPM and also people who is starting to feed
with low dose of nuts and adding more every week. my current
grow is royal dwarf auto in her 55 days, im using SENSI nuts, about 1600
ppm (im using an EC meter and convert it) and she seems to be happy
with that, anyway my question is what is the red line for ppm`s? how much
higher can i go until its too much? and any other info about ppm will be great
for a noob like me. i will upload some pics later =]

thanks all.
Happy grow.

Watch for signs of burn and then back off.