Grass feed rust stains on concrete

Question

Applied recently "Scotts® Green MAX™ Lawn Food" to my lawn without knowing that the iron could stain my driveway concrete and ended up with some very ugly rust stains after the rain came down later that day.

Here are my questions:

1. Can I expect that the stains will wash off over time simply by being exposed to the elements like rain and snow and if so how long could that take?
2. If not which product would you recommend to remove the stains? So far I tried ZEP Calcium, Lime and Rust Remover found at Home Depot and it did not help a lot.
3. Since there are already some chips in the concrete that would be nice to fix, would it make sense to get a contractor to coat the concrete with a thin layer which would also cover the rust stains and how much does that cost per 1000 sqft?

Answer 1

CLR is what you're looking for. I had a similar problem as you (I was cutting metal on my driveway and did not sweep up the fines that night...Rusted the next day!) and it worked like a charm. It comes in a grey bottle with a multicoloured label.

Dilute using the measurements on the bottle, and scrub hard with a stiff bristled broom. Rinse well. This stuff is awesome elsewhere in the house too - in particular to clean up around taps.