If desiring to use distilled water - NAPA MAC's 1300
https://www.napaonline.com/en/p/MCC1300
Has been frequently mentioned previously on the Barn, additionally I add a bottle of Red Line Water Wetter. Usually flush/backflush yearly.
As needed white vinegar or thermocure flush//backflush.
Winter storage drain water and fill with antifreeze, in spring drain antifreeze and save it for winter-reuse.