^Clearly the silky rooster is dumping iron into you're water to distract you so he can mess with your kids 
But seriously. I am completely stumped here.
There's just no way that .15 ppm at a ph of 7.5, which is really not high, in a freshwater fill should be staining that quickly.
Did it happen almost immediately, or just after you added more salt? What kind of salt are you using? Did it happen before you turned your swg back on? (Or have you yet?)
I don't recall if I asked before but is your swg bonded correctly to your system?
Is there any chance you have corroded dielectric pipes running to the exterior spigot? Was the tap water sample from the outdoor spigot, or in the house?
At this point, my hope for you is that the Jacks Purple nails it without wearing off fast. But I'd sure like to help you get to the bottom of the source
Also, when you add the jacks, start out with just one bottle to see if that works, and pour it entirely on the steps.
The reason I'm suggesting this is that depending on percentage of water change, you still have some sequestrant in there...you might be able to get back to the sequestered effective level without a fresh full dose, and then use the rest for small weekly top ups.
Just trying to stretch out the $$$. 1 bottle, so a little under half dose in my case, totally nailed the steps.
But seriously. I am completely stumped here.
There's just no way that .15 ppm at a ph of 7.5, which is really not high, in a freshwater fill should be staining that quickly.
Did it happen almost immediately, or just after you added more salt? What kind of salt are you using? Did it happen before you turned your swg back on? (Or have you yet?)
I don't recall if I asked before but is your swg bonded correctly to your system?
Is there any chance you have corroded dielectric pipes running to the exterior spigot? Was the tap water sample from the outdoor spigot, or in the house?
At this point, my hope for you is that the Jacks Purple nails it without wearing off fast. But I'd sure like to help you get to the bottom of the source
Also, when you add the jacks, start out with just one bottle to see if that works, and pour it entirely on the steps.
The reason I'm suggesting this is that depending on percentage of water change, you still have some sequestrant in there...you might be able to get back to the sequestered effective level without a fresh full dose, and then use the rest for small weekly top ups.
Just trying to stretch out the $$$. 1 bottle, so a little under half dose in my case, totally nailed the steps.