I sure do! I put a small capful of Clorox bleach in the 55 gal. when it's full. This keeps the water potable for them. I have been doing it that way for over 2 years and it works great! the water cools down at night and i have cool water for them in the mornings. I do clean it out about once a month with a broom handle and kitchen towel to keep any scum or algae off of it. If we dont get enough rain to keep it full, i drag the hoses down and fill it up. It willkeep me in fresh water for the month.
In winter i empty it out and flip it over so that it doesnt freeze tons of water inside. That is when i have to carry buckets a few hundred feet for them.