Review on Stay Informed About Water Temperature With Blufree Floating Pool Thermometer - Perfect For Pools, Baths, Spas, Hot Tubs, Aquariums & Ponds by Justin Elmore

I bought this for Koi pond in October of 2019 because it was so cute. It worked fine in my pond last winter, and I was able to monitor the pond's temperature. I took it out when spring arrived and the pond warmed up, and I put it my other koi supplies/chemicals. But I put it back in the pond in September, and algae has quickly grown inside of it and I cannot read it.I keep my pond very clean, and algae isn't a problem anywhere except within this cute little thermometer. I've tried wiping it clean but the algae is on the inside, where I can't get in to clean it.Really disappointed.But you get what you pay for.