Very true and very important, I always use the water from my tank; have been doing this since the boat was new. We don’t drink the water but could. If the previous owner did not do this you may need to clean your tank, and flush quite a few times.
I still use the pink stuff for the left over water in the fresh water tank, and then I blow the lines out. In the spring when I re-commissions the boat I fill the tank twice then flush it, then put some bleach in, fill the tank, let it sit for a day, then flush two more times. The result is the water is perfect.
