Hi

@JoshP12 Thanks much appreciated. I am still trying to figure this one out..

I did some rudimentary testing earlier today. I made two buckets of 10 liter of RO water @ TDS 7. Amounts below measured out on a fairly accurate microgram scale and tested using the fairly inaccurate API pH and KH test kits. However the TDS checks out almost spot on using my Hanna TDS meter vs the amounts of Potassium and Carbon trioxide in the K2CO3 that I added.

Bucket 1: To increase the KH by 1 I added 0.25 gram of K2CO3 and measure a pH at about 7 (could be anything between 6.5 and 7.5) and measure TDS at 32

Bucket 2: To increase the KH by 2 I added 0.50 gram of K2CO3 and measure a pH at about 9 (maxes out the Wide pH API test) and measure TDS at 54 (should be 57).

I can draw a line between these two points, but I am sure there is a more rigid mathematical correlation here. ? Even though I studied up quite a bit on basic chemistry lately, I realize I am still just mostly a math and computer science guy

Cheers,

Michael