We have all seen steel readily rust in water. Perhaps you’ve seen after installation well casing videos where rust formed at welds and at areas where the casing was scratched.
There are areas where the pickling of the metals was damaged, and elements of the water are causing corrosion. The corrosion is demonstrated as iron, and iron is food source for bacteria. Corrosion cells can also from chlorides, as well as sulfate reducing bacteria (bacteria living on sulfur and forming nodules using the minerals and metals in the water – whose waste can degrade steel at the rate of ¼ inch per 10 years).
Acidifying a well with hydrochloric acid will leave entrained chlorides unless the chemistry has mechanisms to overcome the entrainment. That’s Well-Klean.
It’s stunning what you can do passivating a well after cleaning it. You could also call it pickling. With Well-Klean products, the concerns of minerals falling out of solution or re-precipitating does not occur as the elements are completely sequestered.