I am having problems with my cya. I tested this morning and got a 50 I was outside in the sun with my back to the sun, I tested this afternoon again outside but there was no sun to much cloud coverage and came up with around a 30. I know the 50 was rite this morning cause I poured the solution back in the bottle and checked it about four times and it always came out to 50. Does the sun make that much of a difference on how the test reads?