Jack
Put a mark on the stop tap on your waste so you can turn it off and back to this position you have marked, saves the setting up of your r/o.
I would also put a stop tap on the pure water out and when you have done a fill of your tank. Turn the tap to the off position on the pure water, and open the waste tap to full and let the water flush the membranies for 15min. This will keep your r/o clean. Then reset both taps to the position you had at first.
Roy