Has do you remove a dark stain on the water line of a pebble tech pool?

I have this problem in my pebble tech pool. If you have a over flow valve plug it and fill your pool water level to the dark stain and make sure your chemical levals are good. Run your pool system for a full day this should help take it away. P.S. don't forget to unplug your over flow. I hope this helps

Well, it may take a bit longer than a day, a week , a month. You also have to scrub the tile line with a tile brush or a tile scrub pad and swimming pool tile cleaner( "tile soap"). Depending on the deposit it may take you all summer. This dark line could also be from a sliver type algaecide used to control black algae. If you did not follow the label instructions you are in for a lot of hard work. If you have not been cleaning your tiles on a weekly basis you probably have a calcium line also with the added part of the algae killer silver. It should come off in time tho.

k