How do I clean algae from my concrete birdbath?

I have tried different cleansers as well as brushes to clean out my filthy birdbath. Nothing does the trick! No matter how much effort I put in to cleaning it, it still has rust and green streaks of algae all over it. I have put copper pennies in it to slow down the growth of algae. That was useless. The birds have never been attracted to this bath. Not even when it was new. It's tempting to give up on trying to make it a sanctuary for the birds, and just grow a plant inside of it instead.
What do you suggest I do? Thanks!

Hi Catlover. I inherited a broken concrete birdbath when I bought my house several years ago. I had to reset the bowl on top of the pedestal, and over time, it has become a widely used drinking and bathing spot for my birds. It is not particularly clean - I spray the poop and algae off as much as possible when I refill. But the birds are very happy with it as is. I suggest staying away from chemical cleaners. My birds prefer a shallow birdbath, so if yours is a deeper one, try some small rocks for the birds to perch on in the bowl. I did buy a new ceramic bird bath that was much deeper than the old one was, it was not well received. It took about a year for the birds and squirrels to start using it, but it is now a well used mainstay in my front yard. Hang in there.

I too avoided any chemicals, but then we got sick birds about a month ago. I broke down and used the 10% bleach solution. Bird baths, feeders both got it and I let them air dry before filling up again. Is your brush wire? The softer bristles are not very helpful.

I talked to others about avoiding bleach and they said nothing else will kill the bacteria. Not even vinegar will do the trick. You can use a wire brush alone to remove the green algae, but it is only a visible improvement. Even after the bleach treatment, heat, whatever bacteria from the birds and leaves, grass, etc., the algae grows back. In the heat of summer, if you want a bird bath, you need to maintain it. It is work. It took us a long time to get to that point of-do we want to do this?

I've got rust spots and they don't bother me or the birds, so just let those be.

It does sound deep if you think you can plant in it, so the above suggestion is good. Is it on a pedestal or on the ground? We found our concrete bird bath on the property after we moved in. It had no pedestal, so it's always been on the ground. We put a heater in it during the winter. We also have a smaller bath with a plastic insert. Many will drink out of it, but only the bigger birds bathe.

Hydrogen peroxide is better than bleach, as it doesn't leave any potentially harmful residues. But first, a kettle of boiling water and a scrubbing brush to get most of the gunk out first.

Resin

Resin, I had never heard that before. Will it really kill the bad stuff? I want to find a less toxic solution for cleaning the bird baths, but I want sick birds even less.

I find that my birdbath in the shade has less algae than the one in the sunny spot. I also use 10% bleach solution and it works well for a while. I'll try hydrogen peroxide next time. Thanks Resin and everyone else.

Good information about the hydrogen peroxide, Resin.