Charlie_R, thank you for taking the time to post this -- very cool! I had been wondering about using defunct units as filter housings; interesting to see that you have had success with this approach.

One question, regarding multiple return points -- does that mean you had to cut additional opening(s) in the pool liner? If so, no problems with doing that in a non-reinforced spot on the pool wall?

Since we happen to have a donut pool (LOTS of wall movement with swimmers in the water) we wouldn't be able to do hard plumbing all the way up to the pool... but your setup gives a lot of food for thought. Thanks again for posting the description and photos.