Stain from a Soft water tank Leak

I have a customer who had a soft water leak. The soft water unit is in the garage and the adjoining wall is the office. When I got there all was dry, but the carpet had a stain. The stain was not your typical soft water stain. The stain had a tinge of brown, to slightly red, I think it was the stain from the built in wood wall unit, as the color was no the edges of where the water stopped. The customer does not want to replace the pad, nor remove the wall unit to replace carpet. I have...

Stain from a Soft water tank Leak