IRON OUTPowder Rust Stain Remover, Remove and Prevent Rust Stains in Bathrooms, Kitchens, Appliances, Laundry, and Outdoors, 4 Pound 12 Ounce, Pack of 6

I use this everywhere as we have very hard well water even with a softener. I pour it in a spray bottle and turn on the exhaust fan, and put on an n95 mask. I spray it in the shower and toilets and start scrubbing after letting it sit for about 10 minutes. It takes most of the rust right out! The only downfall is the smell is extremely potent so keep the bathroom door shut and keep pets and kids out until it has time to clear the room.

I have been using this product for 20+ years - for multiple things - most importantly to clean my water softener. I do that once a month using the "manual recharge" on my unit. I dissolve about 3/4 pound of Iron Out in warm water...then dump it in the brine tank before that tank fills and begins the backwash cycle. It cleans the resin beads (plus the valve assembly) completely and extends the life of my water softeners by 5 years longer than normal (at least.) For curiosity, I weighed each of the six 4.75 pound bottles I just bought. The weights varied between 4 pounds 14 ounces (minimum) to 4 pounds 15 ounces (maximum)....with 4 pounds 12 ounces being equal to 4.75 pounds. After allowing for the weight of the plastic jug (very little) my conclusion was "The mfg. is NOT cheating anyone on the amount of product in each bottle. GREAT STUFF - GET SOME!!!

Works in water softener