What would be the recommended length of time for me to water fast?

Hi, I am on day 2 of my water fast, Does anyone have any suggestions of what would be the best length of time to carry this out? Im not sure if I should do 10, 20, 25.

I did a Water Fast for 11 days 3 months ago and I have been eating healthy ever since (apart from a slip up here and there). Im not over weight and I don't smoke or take meds.

Recently I have been breaking out pretty bad and this hasn't happened since the water fast, in fact my skin has been the clearest its ever been, I think maybe the days that I ate dairy and sugar/ salt might be the cause but this was only a few times, also I notice that if I eat any food with salt in it I swell up, even my face and under my eyes get puffy! anyone else experience this?

Im 5'9 and today when I weighed my self I was 121 lbs which is average for me since my fast.

Any feed back would be greatly appreciated! :)