I am in a ebb and flow system with 12 buckets. My ph seems to go up each morning when I check it goes up to 7.0. I bring it back to 5.8 each afternoon . I do 4 water cycles for about an hour each. Is that a normal ph fluctuation? I am in early veg. stage. Under 400 watt halide and 2 T5 sets. I ordered a ppm meter when I get it what should my ppm be kept at?