Quick update on this:
we met a few pool vendors and we're about to pull the trigger. I decided to go ahead with my "sump" in the shed. I'll get a local steel fabricator to build it, and the pool installer agreed to help me in my project. I'm not getting a P4 and will only get the chlorinator since I'll be making the controller myself. I'm also gonna get a variable speed pump.
right now i'm struggling with my arduino on a few things. those being: ethernet module (enc28j60) being a real b*tch to work with. I'm gonna have to get a "real" w500 one I believe. I also received my phidget probe adapter and I tested them. They seems to work fine but until I get both my Ph and ORP probe there's no way to tell. I'm also having some difficulties with a relay boards I got which was suppose to turn on/off 110V electricity based on 12V input and 5v signal but I'm not sure why it is not working. I just received a few SSD relays that I'll try right after this post. Last problem in the queue is a set of LM35 I've ordered. out of 5, only 1 "seems" to work "ok". Shitty crap from china. I knew 3$ for 5 sensors out of ebay was too good to be true!!
nothing really relevant to anybody reading this post but just to let you know that i'm moving forward and that you should expect some nice pics of the building. I've started working on the enclosure, my water level code is done, if the SSD relay works tonight I should have the initial release ready to show you.
stay tune.