I read that "a TDS meter measures the conductivity of the solution and estimates the TDS from that." - is bio-contamination (feces/food) conductive?
I'm also of the opinion that clean water (free of bio-contaminants) is key.
funny, I'm having a similar experience......I now know more about water parameters than I ever dreamed! I started talking GH/KH, pH, etc at work yesterday and got some funny looks LOL!!! (btw I work in Surgery/Operating Room nurse )I now have a little more experience in a new field that I knew almost nothing about a few weeks ago. This has brought me to a point where I see the picture a little better (at least I hope so) and as a result have redifined my objective somewhat.
good luck with this Paul -- your thorough systematic approach really appeals to me. looking forward to reading more!