Join Date: Jun 2015
Location: Atlanta GA, USA
The Gh and Kh will show part of your TDS and is a good estimate of how soft/hard your water is, but the TDS will show everything. They are only $7 on amazon...
The best way to lower TDS is to use RO water which can be purchased at many LFS (particularly Saltwater fish stores), around 25-50 cents per gallon.
But unless you have REALLY hard tap water, no need to alter the parameters...