Rain Barrel

[Jennykenny]

Have had a rain barrel installed in the garden connected to a downpipe from the roof. It is great. Wish I had done it years ago, but if I don't use the water quickly enough it gets a bit smelly.
Heard that if you put charcoal in it, that works?
Any other suggestions.

[Buenchico]

The RHS suggests the use of potassium permanganate crystals to reduce the build-up of algae:
https://www.rhs.org.uk/advice/profile?PID=731

[1ozzy]

Really shouldn't get stinky quickly. We have nearly 42000 litres of rain water tanks here to supply our house with water as the town supply is terrible. Ensure there is a filter on the inlet and overflow and no light can enter. Algae cannot grow without light. A first flush system is also useful. the first flow of water from the roof is diverted away from your tank, about 10-15 litres, this reduces the amount of dust, leaves and what ever else lands on your roof and guttering ending up in your tank.

[Jennykenny]

Thanks Ozzy. Had been leaving the lid off so that when it rained it would catch extra water (duh!). So won't do that again.
And Chris thanks for your advice.