high ppm in runoff coco grow~ADVICE PLEASE!

Hi~ this is my first post! I need some wisdom from the pros here....im a first time coco gardener (but not a first time grower) and so am still trying to figure out all this ppm/ph craziness. soil was so much easier!! so heres where im at:
30/70 pearlite coco mix
3 gallon pots
3x600 hps
drain to waste
5 weeks into flowering with green crack
using GH nute and feeding schedule (with a few alterations)
watering daily
ph of res. is 5.8-6 (tap water)
ppm of res is around 1000
AND HERES THE PROBLEM::
ppm of runoff is 2200.
i have flushed, and flushed and flushed and got it down to about 1600-1800 but how long can i flush for? dont i need to feed them too or are they getting plenty from the nutes in the coco? basically im flushing each day with ph'd tap water, no nutes, until i cant stand it anymore~ this is very time consuming due to my crappy drainage system. its been 3 days now. then i was wondering, do i even have to do this since in draining to waste? What is an acceptable ppm of waste water? what should the ph of the waste water be? how do i prevent this from happening again? i water each day until some water is coming out the bottom so theres a good flow going through. i dont let them dry out. how does this happen? thanks for any insights you might have. bless up!

if you were flushing,it should get alot lower than that,you can flush for as long as you need to
anyways,are you seeing problems with the grow itself?if not,i would not worry about it

yeah, theres some minor problems~ def. some over fert problems showing like brown curling of a few lower leaves. im concerned because in the past, with every grow, i have major fert problems by the end. i only learned fairly recently what was going on....i just want to avoid that again. im just curious what could be going on? why arent the plants using the nutes? ph seems spot on...

because u are feeding them too much
try feeding a lighter dose
or water a couple times in between feedings and a flush when switching to flower will help with the accumilation problem......
u said u have been flushing for 3 days?u should not have a ppm that high
can u post some pics???