Rust stains caused by coins!

[PoolDoc]

Janet, pennies don't have iron in them; they are copper plated zinc . . . so those stains aren't rust.

Vitamin C still may help -- not sure whether the stains are copper or zinc.

Ben

[aylad]

Yeah, I get that....my point was that the Vitamin C thing is just the easiest thing to try first.

Janet

[PoolDoc]

ok -- it would be interesting to know if VitC removed those . . .

[waterbear]

I assume this is a plaster or fiberglass pool, correct? If it is then the following applies:

Maybe the zinc, copper is doubtful. For those, dry acid in a sock might work. But try the vitamin C first. No need to crush it, Just put a handful in an old white cotton sock and hold it on the stain. If it is going to work it will do so in a minute or less. Use your pool pole to hold the sock on the stain if you can't reach it otherwise.
If that doesn't work put a handful of dry acid into another old white cotton sock and hold it on the stain for up to 30 minutes.

In any case, adding a double dose of metal sequestrant can help over time.

If you have a vinyl pool then you can use the vitamin c but do NOT try the dry acid!