I recently went this route(I live in Texas). I bought the 1 HP Submersible off Ebay for $22(shipping included). It was missing parts but I didn't care. I went to Lowes and found what I need. A mock up and then glued together and it was a go.
I use my Mashtun to hold the ice water. I use my garden hose to take the initial temperature down, then I switch to the chiller. Works like a champ.