Rust Spots on Main Drain

[klovell]

I have a few ... 3 or 4 rust spots on the edge of my main drain. Not on plaster. Does anyone no anyway to remove the few spots?

Thanks

 

[BoDarville]

Since I would first suspect metal staining and since they are on the main drain at the bottom of the pool, try dropping a few vitamin C tablets (which contain ascorbic acid) on the stain and see if it lightens after a few hours. That would indicate metal staining. Turn pump off when doing this since you do not want the tablets to move off of the main drain.