Hi LuLu
I test every batch of bleach I buy ---- Using 1000 ml (1 Liter) of UNCHLORINATED water (from a well or distilled), place .1 ml of the sample from your bleach bottle -- mix and test.
As for the dilution method for testing bleach I use a 1000 ml volumetric flask and a medical syringe used to perform the standard tuberculin “Tine†test. The syringe has a total capacity of 1 ml but is graduated in .01ml graduation intervals with major graduations at .1ml. The dilution method is accurate within .1 ml @20 deg C.
Testing is done using the FAS-DPD method, using a 25ml sample size, again yielding accuracy within .2 ppm in a 10000 to 1 dilution.
I have found the results to be repeatable with a 95% confidence level (in scientific terms [95 out of 100 tests]).
The results of the test is equal to the percentage of bleach.
Most Clorox Ultra tests around 6.5%