I don't think you can line a foot spa that has jets.
The only two that I know of that use liners are the Footsie and Belava. They don't have jets but they do keep the water warm and they 'agitate' (can't think of the correct term) the water w/o jets. HTH!
So its obviously not a good idea to get a foot spa then. But then again when people go to the high street salons those fancy spas arent being lined either i never complained when i was using them neither. I would disinfect after each use
Obviously you can disinfect between clients but I like the fact that I can do back to back pedicures without the need to disinfect as I just change the liner. It's all down to personal preference but also a great selling point to my clients.