This morning every single person about to enter the outdoor pool did a double take. “Green!” Quite a pretty green, too, as if the water was on top of a freshly-mown lawn.
The water seemed normal, and people were swimming in it already, so I just got in. We developed the most outrageous theories: is it St Patrick’s Day? (no, that’s March 17.) It needed a new coat of paint anyway, so why not a different colour? Someone boiled their spinach in it, for an orphanage! ten orphanages! We’re swimming in primordial soup! It’s a special effort for Easter! (Jan the Warm Water Man fuelled that one by saying “we’ll have orange for the Queen’s birthday and red for May Day!”)
The real cause was a lot more prosaic, of course: they filled the shallow pool in preparation for opening it for the summer, this dislodged algae from the pipes, some of the water got into the deep pool, and the algae thought “Wow! Lots of room! Let’s go forth and multiply!”
It didn’t make the water unhealthy to swim in or we wouldn’t have been allowed. It was a bit cloudy under the surface, harder not to bump into people when doing crawl. And it did start smelling a bit vegetable when the sun shone on it.