Well i cant answer, nute as your plant tells you, looks like you could get away with upping the levels a little but why screw with somthing thats got you this far. Ask other growers or just go with what experience you have, too tricky for me to call, too much and your screwed and too little and well small deficiency. I grow in small pots and make sure i dont get salt buildup by getting one third runoff plus small plants dont eat a lot but with the rest your on your own or take others advice.
I will say this about tap water and that is that it is different to distilled water, it has calcium and magnesium in and other elements that are good to the plant in small doses, about 100ppm to 200ppm normally means good quality tap water for plants, i could go on all day about water but if i just post the link it will be easier for you to read up -
https://www.rollitup.org/general-marijuana-growing/294579-water-most-essential-compound.html
And i dont post links for the hell of it, all the info about tap, distilled and filtered water is in there, either hit me or Doc111 up if you need more help understanding it.
I do love these plants though, still flowering with that 150watt hps???
If you are you have done really really well, lovely productive small grow op, congrats and great pictures, loving the bud porn and reckon you got a lot of things right to get to this stage, keep it simple and im sure you will reach that magical harvest. Peace