I recently got a water setup and I used some PC chill (uv green) to fill it. Within the first day the color was not UV reactive. While at microcenter I saw some fesser UV dye and decided to get some. I Put some in and within a few days the color fades away. I am not sure if I am putting enough (about 10-20 drops) or is this is normal. I dont want to keep adding it if its not good for the loop since is does have glycol in it.