Bought this to put in the toilet sea water filter and it works fine. Because it's the concentrate, it's a bit thicker and doesn't dissolve as quickly. The diluted Pury Blue had significantly less effect.
... in the case of a longer absence in the toilet or the sink and the air is clear when we go back on board. There are no longer any limescale deposits.
Application is in southern Spain and we have already tested various means. Purysan works best against odors and unlike some other remedies, the toilet seals are not affected and no deposits are formed on the seacock's ball.