Is the water sprinkled with the hyssop or is the blood or blood diluted with water sprinkled with the hyssop?
What's your answer to your question? And if you have an answer, why ask me?
It seems in one reference that blood is involved, though whether it's blood diluted with water or water with blood in it - in other words the ratio of blood to water - is not clear. In another reference it seems that the ashes of the sacrifice and some other stuff (red yarn) are involved.
I maintain that the argumentative circularity, which is my main point, applies in either case.