Any thoughts on this? I have a lot of trouble with the CYA test, do I see the dot, or not. I get good results with a slight modification:
Prepare the test solution as usual, but before putting the drops of the mix into the tube, place the tube on the taylor stirrer with the light switched on, but no stirbar. In a semi-dark room (my kitchen with the lights off and the shade drawn works for me) continue the test as usual, looking straight down the tube from close range. As you get close, move the tube very slightly side to side if you are unsure when the dot disappears.