It does get a lot algea inside. The water I have stored was from this past spring and its almost used up. I was told that there is algea tablets that can be used but we've not tried that.
Here is mine so far. Pics were taken a little over a week ago.
Still have a couple of weeks before i get any thing out of our corn. Getting a lot of sguash, tomatoes, and a lot of cayenne pepper. The beans we have growing on the cane poles are lima beans. I planted some mississippi silver skin...
I'm using an old 30-gal garbage can, and also drilled several holes along the side and bottom. I put my everlasting supply of chicken poop grass clippings and scraps from the vegetable garden. Rolling the can around on its side works well . I think this works just as well as one of those...