Oh my, with such a statement I wonder how that will effect the situation.If you can't distinguish the difference between the amount of water between the two i'm done debating with you. Kakashis suiton served it's purpose in defending him from Kakuzus attack, and the difference between the water mass of Kakashis suiton and water dome is enourmoss.
I'll say it again, by the time Kakuzu and Hidan realize that the water dome moves with them and decide to swim oposit directions; Hidan will be shark food and Kakuzu who needs to breath will be losing oxygen as well chakra being drained from him and is defenseless against GSB. GG, Kisame potentially solos.