I have a garden pond that suffers from “pea-soup” algae. A thunderstorm recently flooded the nearby road, overflowing into my garden and the pond. The next morning the algae had gone. What was in the floodwater that managed to clear the algae?
Colin Carter, Marlborough, Wiltshire, UK
We pay £25 for every answer published in Âé¶¹´«Ã½. To answer this question – or ask a new one – visit newscientist.com/lastword. Terms and conditions apply.
This article appeared in print under the headline “Pond skimmer”
Advertisement
Topics:



