Wouldn't concern yourself over the foam color. There is something in a Red can with yellow cap called Great Stuff. This is an expanding foam truly no different than the balck foam. The Great Stuff looks white originally, but as it dries and becomes exposed to air and UV light, becomes more mustard color. Fortunately, this foam tears apart easier than the black stuff. Just use the Great Stuff. Less expensive and in a year or 2, will become so algae covered that you'll notice it less than the black foam. I swear by it.