i've re-read this thread, and well..... i saw very few references to you allowing for run-off, except when talking about flushing. there is only one way to get the high ppm's you were talking about, and that's from a lack of run-off, period. you don't flush coco, this isn't soil. tap water is usable, but why use it, lol??? all of the ppm in the tap water is just that much nutrient solution you can't use from the bottle. and cal-mag, lol. i don't get why you're using it. you're in coco specific nutes, you don't need it. you're in coco specific nutes, you don't need it. i also remember you talking about it being cold. i'll assume you are making sure your lights off temps. are within range. having your containers on cold floor/cement, can really cool the root-zone, not good. coco basics; ph to 5.8. "always," allow for a good 10-15% run-off at every feed. don't flush until the end, and don't use plain water. don't use high feed ppm's, it's coco not soil. fresh air/airflow important.