Colossians 1:
16 For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him:
17 And he is before all things, and by him all things consist.
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I read a random idea about putting vinegar into bird baths to minimize algae. I made a comment that vinegar is not good for birds, especially during nesting season because it absorbs calcium. That was not taken well by one or two people.
An image is worth a thousand words, but sadly I never took a picture of the egg we removed the shell from. Click on this link to view someone else's.
How to make an egg bounce!
I admit a few sips of water will not cause this much shell to dissolve, but think about the birds! They have it tough enough already because of our actions, intentional or not. Do not risk future generations of birds just for the sake of easy cleaning birdbaths.
Go ahead and replace bleach with vinegar for cleaning the bird bath. Use a wire brush to give it a good scrubbing. You know you need to work your arms muscles as much as I do. 
Then rinse the bird bath as well as you would if you used bleach. No harm to the birds.
This was my favorite birdbath, but temperature changes caused it to crack. We tried caulk that was deemed safe for plumbing, but it would come off as we scrubbed. It was a freebie left here by the previous owners. I have been on the look out for another like this, but nothing so far. The birds prefer the bath close to the ground, so I don't use a pedestal. We do not allow cats to roam here during the day, so that has not been a problem.
