This is a farely new tropical aquarium that has been setup for about 3 weeks, the tank itself has been around for about half a year not been used until now and I noticed a white/grey fluff forming on the ornament shown, a little on the other ornaments too. There are no fish or no food that have been put into the tank. It's a 64 litre tank, I haven't tested it with test strips. I will try and give more information if needed. Thanks for the help.