My pool store said they don't provide the valves as standard equipment because people forget to turn the valves back on and can damage the pump by letting it run dry.

I did not opt to add isolation valves because I have a 4 year old that likes to do what dad does so I'm afraid he would turn the valve off someday without my knowing it (despite being told he's not supposed to touch the pool equipment).

Instead I got some rubber stoppers at the Home Depot - one to fit in the bottom of the skimmer and one to fit in the return jet eyeball. I put a screw eye in each stopper and tied a piece of polypropylene line between the two (for two reasons - one to clearly show the stoppers are in the pool and two in case the return one fell out or was dropped it won't go to the bottom of the pool.) It's cheap, easy, and I don't have to worry about valves getting turned off at the wrong time.

Peter