Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
I am not sure how the TDS meter creates its read out, but you are right, it is testing for charged particles and we are pretending that this is all the dissolved solids. I remember reading somewhere that most TDS meters convert their test into a number that is the equivalent of all salt in the water, not a mix of ions.
I wonder if it is really important exactly what it is measuring?
The way I use test results is that I am comparing today's readings with the test results from last week, and the weeks before. If there are changing results, then I look further to see what is happening.
Do you have a TDS meter that you could compare the two sets of readings and see exactly how they are related?