diluting samples during testing


Well-known member
Nov 13, 2011
Sabina, Italy
Good Morning,
I use a LaMotte color Q, tablet version photometer testing kit here in Italy. I can't get a Taylor kit for love nor money without importing it personally and commiting myself to hanging around Italian customs sheds for weeks.
Generally I am quite happy with the Color Q but one of the Color q's limitations is that it only reads up to about 10 ppm FCL, which is difficult when shocking the pool into submission, 'HI' is not useful data...
My questions are: 1/ is it correct to dilute the sample with (a) distilled (de-ionized) water or (b) with more pool water ?
2/ Are the results proportional in respect of FCL and TCL, i.e. doubling the sample volume for one tablet of reagent halves reading. I appreciate that with Ph this isn't the case but this is not a problem.

A quick explanation of the answer to Q 1 would be appreciated, I get what seem to be more consistent results with distilled water.

Many thanks for any help you can give.

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
SouthWest Alabama
You introduce a margin af error by doing that but it's still ok to use when shocking. You want to use chlorine free water for the dilution. it doesn't have to be distilled water.