Wow your are experiencing the same exact thing that has happened to me. Same Rad and same dye also. Hmmmmmmmmm.
As you can see from my 2 month experiment I have narrowed it down and you just help confirm it.
yes the first time I used my dye with Dtek rad I came home from owrk the next day and my water was crystal clear. I was like where did that dye go. Then I was told that air in rad can make the dye disappear. So I began all my testing. The more people told what was wrong the more testing i did and I started doubting other peoples advice b/c they had no facts or test results like what I was gathering.
Shoot Im almost a UV Dye (Green) pro now.
if I can create some kicking blue many people will Like That.
OK Im off my high horse now.
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