Rain Water Collection and Keeping Clean ?

[PaulZone8b]

I have several black pickle barrels (55 gal) collecting rain from house (shingles) and barn roof (metal)...but after a couple years I am finding them getting algae and stinking. I am ready to clean them out, but wondering what others do (or add) to the barrels to keep them cleaner (less or no algae). I have heard adding hydrogen peroxide can help (and safer than other things). 2-3 Tablespoons of bleach to the full barrel works too (if clean water to start with) and add it every 6 months or so. Any thoughts or experience from others on the forum ?

 

[Meadowlark]

My "system" is super simple...but effective for me.

I collect rainwater from roofs in 30-gallon tubs and cover the tub if full or empty. I get limited algae and/or debris that way.