Question about CH test with tf100


Active member
Aug 26, 2011
I ran a Calcium Hardness test with the tf100 kit. I filled the cylinder to 25ml. I added the 20 drops of r-0010. Then added 5 drops of r-0011L. The sample was suppose to turn red but it turned a pale pink. Then I added drops of r-0012. At 25 drops, the sample became clear. I continued to add and stopped at 70 drops and the sample never turned blue. I then redid the sample adding 2 drops of r-0012 prior to adding R-0011L in case of the presence of copper but I had the same results. Do I not have enough calcium to turn the sample red or do I have another problem?


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
The exact shade isn't as critical as the change. When it went clear is probably when it turned blue. You can always add a few extra drops of the R-0011L to get a deeper color. Then the color change should be easier to see. Also, how old are those reagents? If the R-0011 bottle is discolored at all, the stuff inside has gone bad.