I will be installing an Intellichlor IC40 this weekend. While planning out the plumbing I came up with an interesting question. Currently I have a 2" line coming from my heater with plenty of room to add the check valve and the cell. However, this line feeds the returns in both my pool and spa. Do I need to isolate the cell so it is only on the pool returns or just shut off the cell when using the spa? The installation manual doesn't reference a pool/spa combo that I can find. I just don't want to super chlorinate the spa when it is in use