Gardener Left Baffled As Bird Bath Water Kept Turning Red — then The Internet Revealed Why

Bird baths are rewarding additions to every garden. But as beautiful and refreshing as it appears, it is quite a task to maintain the concrete structures planted in many gardens or yards. A tenant, who goes by u/Radiant_Leader on Reddit, hopped on the internet hoping someone would solve their recurring bird bath problem. In a post, they shared a photo of a parched bird bath with red pigmentation on its inner walls. The tenant claimed they had tried to scrub it off, but the red color remained persistent every time the bath was filled with water. People quickly identified the root cause of it and offered a possible fix in the comments. 

The Reddit user claimed they found the old bird bath in a house they were renting. Hoping to put it to good use, they cleaned the bath and poured in water for the birds. However, the red hues returned within days of cleaning. “Any bird (bath) experts here? I have an old birdbath in the house I’m renting, but it has some serious issues. Every time I scrub it out and fill it with water, it turns a nasty red colour within days. Does anyone know why this might be happening? And what can I do to fix it? TIA,” the post read. 

One person (u/Quantum_Daedalus) explained, “It’s red algae. You can soak the bowl in vinegar or bleach, rinse and fill, but with porous concrete, there will always be a bit trapped in a little hole that will cause it to bloom again. Nothing you can do to prevent it short of coating the inside of the bowl with a sealant.” An expert from BirdLife Australia (u/semaj009) identified the problem that was causing the red algae to flourish. “From BirdLife Australia on bird baths, you're not changing the water enough/cleaning it enough, so algae (or potentially diseases) can spread. Nobody gets taught this sort of thing in school or anything, so don't worry about it, but in the future, if you're going to have it full of water, it needs to be more regularly refreshed.” 

Similarly, a few other people chimed in. u/Chooky78 advised putting half a Milton tablet in the bath every few days to keep it fresh. It is also not harmful to the birds. u/ThatGuyTheyCallAlex figured the red color could be a bacterial infestation since the walls of the stony or ceramic are porous and leach out into the water. “Perhaps it needs to be soaked with some kind of killer and then sealed?” the comment asked. “Just bleach it next time and it will kill bacteria,” added u/musofiko. While some others resorted to humor. “Haunted. Bird ghosts most likely,” mused u/Ol_Dirty_Batard while u/hypatiatextprotocol wrote, “You’re going to get some demonic-looking magpies.” 

Red algae in a bird bath are usually harmless, scientifically called Haematococcus pluvialis, according to The Lewiston Tribune. This type of algae thrives in sunlight and turns the water red due to the pigment called astaxanthin. It helps protect the algae from UV radiation. A possible solution to get rid of it could be moving the bird bath to a shadier spot or simply cleaning it regularly with vinegar or bleach to keep the bath fresh.