Look at the chemical structure of Dichlor
here and of Cyanuric Acid
here and you will see that dichlor is essentially CYA with two of the hydrogen attached to nitrogen being replaced with chlorine. As Dr. Spa noted, CYA is one of the chemical components of Dichlor -- it's not a separate ingredient but a part of the molecule that is Dichlor itself. You might show your swedish hot tub forum friends this info to help educate them and stop the B.S.
In water, Dichlor partly combines with water to form hypochlorous acid as well as cyanuric acid (and other combinations of the two).
