Interesting because there is a chlorine shortage here in the states used for commercial cleaning and pool filtration. We have been using industrial liquid cleaners since our troughs become contaminated with algae due to the high heat here in Central Texas; however, it is no longer available. We are back to Chlorox-type products which have been diluted from former concentrations (approximately 2 years ago) because of the toxic fumes. (Apparently people don’t know not to put their noses over the freshly opened caps). Probably why diazo machines are no longer in use, either.
