"My question is, would it be effective to Water Fast for as long as i can then break with some juice for a day or more, then go back to water and continue this cycle? would this be effective?"
Staying in water only would be the most effective, but if you absolutely had to break with some juice, then return to water only, this would no doubt provide an excellent cleanse as well.
Just know that each time you break, you disrupt the desired state of ketosis and each time you then go back into water only, your body needs to re-transition back into ketosis. I believe this is the single greatest reason why it is so much better to stay in water only at all costs. That and the fact that cleansing is about 3x more powerful in "water only" than in a juice diet.