I agree with Stinkster....go with RO or distilled.....200ppm may well be what's causing you issues.

And did you presoak the living shit out of your hydroton to stabilize the ph?
Weedhound Reviewed by Weedhound on . Troubleshooting Form and my Resignation E-indoor or outdoor? Indoor E-soil, soilless, coco, aero, or hydroponic Hrydro E-specific medium hydroton CSL-Soil type/brand HCL-Hydro/aero/soilless system type dwc SCL-Anything you have added to the soil SCLR-Soil or slab runoff pH E-Water source tap yuck E-Source water pH 8.0 HRT-Source water EC (if hydro) 200 ppm Rating: 5