We had a hard rain the other night, first in months. It brought the pool level up three inches. I used a garden hose to siphon off the excess water, started the pump, added chlorine, and have been watching for algae, but seems to be okay. However, the rain did leave a narrow greasy black ring at its top level around the sides of the pool and the inside of the skimmer basket. The ground here is black clay, and it has not rained in a long time, so the greasy black seems to be just a collection of dirt, pollen, etc that had been suspended in the air for the last couple months. I want to clean it before it stains the liner. What do you suggest? I was thinking a baking soda and water paste or a borax and water paste, rubbed with a soft cloth. I am able to remove it partly with just water, but not enough to completely remove the discoloration.
Extra info: I tried a spot with borax and water, still have the black ring, just not greasy now. The stain may already have set, so any thoughts on how to remove it? The black clay here stains badly (floors, clothes, walls, etc) and usually requires pretty heavy duty cleaners to remove.