Do not ever put that pink stuff in your water tanks! Despite everyone doing so, it is nasty and leads to all sorts of disgusting growth. After using that stuff the tanks sometimes never recover, I'm sorry to say. The only solution I have found is to buy the cheapest vodka available and pump that through the system after carefully draining out as much water as possible. The vodka water in the spring leaves your tanks fresh and clean tasting and looking. My tanks have big inspection ports
and I have done both--after the pink stuff, yuck! After the vodka, you can drink out of them. Don't believe those that tell you that the vodka doesn't have a low enough freeze point or it will damage your pumps. I have done this for eons in boats stored in New England
and never have had a problem.