Where’s it coming from? There’s a neighborhood that we do a lot of work in that is plagued with rust at 90% of the homes driveway. Something in the soil caused it and removing it is only temporary. At least in this situation it comes back rather quickly as it’s from bottom up. Looks similar
It’s fertilizer most likely and running off
Have a lot of concrete like that here in Central Florida, all from irrigation.
It’s all over the siding Also.
How are you dealing with it?
Honestly, I am just starting out and haven’t had any like that. From what I have heard is the F9, try different dilutions. I’m sure some other guys on here will have plenty more advise than i can give.
Another cleaner I have heard of is Rust Remover Plus.
Geeze that looks awesome.
Used this today not much luck 16 oz in a gallon 
how many applications was that?
I’ve used Rust Remover Plus successfully a few times for concrete
One. I clean it with SH and hot water for organic removal, rinse well and apply Oxalic (soak) with a pump sprayer; do not let dry. Once rust is gone, rinse well.
Thanks!
It comes from the hard pan fill that is loaded full of iron, homeowners watering daily saturates the topsoil & runs on top of hard pan & leaches the iron out of it. Or it could be from the irrigation water looking at the pic you can see the spray patterns
He even posted a video fellas
I’m a little confused, and maybe my terms are wrong. In my area, this coloring would likely be sulfur in water. Now I believe that sulfur in my area is a byproduct of iron pyrite, so would treating iron and sulfur stains be the same? Sulfur water smells like rotten eggs, and the mine damage in my area has caused it to turn complete creeks/streams orange. They have done a lot of cleanup, but the damage is still seen.
I think most people around here use vinegar and baking soda on sulfur stains (tubs/showers). A quick google shows baking soda/vinegar, or borax, but some say wet first. I know there are other products like clr, rusto out etc, just asking basics. Never heard of using white ox until coming here.
I know nothing about sulfur being a byproduct of iron pyrite but treating the stains would likely be the same. If people there are using vinegar at home to remove it and, it works, then oxalic would likely work a whole lot better. My reasoning is that vinegar is an acid but oxalic is a much stronger acid. Most homeowners don’t realize what chems are out there or, what they do, so vinegar is always a popular cleaner at home. I’m sure they’re scrubbing their mixture of vinegar and baking soda but I doubt they’d have to with oxalic. Although, scrubbing is sometimes needed even with oxalic.
When it comes to removing rust most of us on here start with oxalic because it’s cheap and it works well. If oxalic doesn’t work you can step up to a stronger acid like muriatic (hydrochloric). It can depend on the substrate you’re dealing with though. You have to be careful because muriatic will etch concrete. The best product available to us for rust removal is F9 Barc which I believe its main ingredient is phosphoric acid. With rust it’s basically all about starting with a weaker acid and working your way up. I bet if you compared the vinegar/baking soda mixture to oxalic on the stains you’re dealing with in your area the oxalic would blow it away.
