Ok thanks, I'll give that a try. I have a water store nearby, or if I put a water purifier on that tap, think that would help?
probably not, K+ is way too small to be filtered out by anything but RO.... Usually the water pipes outside are bypassed so as to not waste the softened water,....
What's the distance from the tops to the lights? This can be a contributing factor if too close,.. what's the T and RH% as well? Bad vapor pressure deficit (VPD) can do the same,.... I see tips burned too, but that's could be several things... P defc. can behave like this too, drawing from higher up leaves and paling out, getting larger necrotic patches,... even though it's a mobile (within the plant) nute and usually drawn for lower leaves like N defc. does....
Bottom line an in-pot pH is needed, and as mentioned, with the ion load going in, there's a chance certain nutes are not getting taken up well,... If you decide to do a flush, use low ppm water for sure, and test both pH and TDS of run-off a few times as you do this,... initially this will give a ballpark estimate of pH, and if your run-off ppm is crazy high, that answers some questions right off the bat... until some of this is known, adding more nutes (like PK booster for P) may make matters worse....
