PPM going up when pH down water

[freakinchina]

hello everyone..i m new here and new to growing...only a year or so....here s my problem maybe someone can help:
i m in deep water culture..3 big bang and one vanilla kush

living in sub tropical climate..so very hot and humid here...i have 2 water chiller for my tank and air con always on...water at 22 and room at 26

the problem is with my water i think...when i buy it, those 5 gallons bottle, ppm is 143 and ph 7.3

by the time i ph the water down, my ppm is 350
so if i get it, the solution to ph down does contain element, so ppm rise.....my question is: the plant doesnt need those element, right?? or does those element can still do nut burn?

 

[GCYODA]

to high ppm of water, no telling what minerals are in there, get yourself some rain water or a filter to clean your tap water