Hi,
with regard to Hotels I just saw your post. If you have not been to calis before you will find that it has a fantastic cheap Dolmus Service. (minibuses) that go everywhere. So, dont limit yourself to only Hotels almost on the Beach! Certainly within your budget would probably be the Rebin Beach Hotel, I have stayed there for the past 3 years, mainly because of the value for money and the quiet location. It is a short walk to the Beach and the Dolmus stops opposite. Has one of the largest pools in Calis but no water slide I am afraid!
I will send details later as a bit pushed now.