You do that. However, you can run the risk of salt crystals clogging in the sample line due to no movement in the lines. The supply line water can start to evaporate, leaving salt crystals in the line, creating a no water sample error. That is why Manual Mode is used after a shutdown.
Now, with that being said, the temp here in the Bay Area is low due to the rain, so I would assume that this week there will be very little evaporation in the sample line and you will be fine. Just make sure you don't go too long in manual mode, or you will most likely have issues. I did this myself just last month. This is why I suggested the other option, as it keeps things flowing and get an alarm if I forget to change the reagent. .