Clorox bleach!
Well, I don't know which of these things keeps the bed white, but I have all the windows in that room blacked out, no sunlight direct or otherwise on the tank. I use Chemipure Elite, bio-pellets in a Phosban Reactor, and I occasionally have to clean the front of the glass beneath the sand bed, but not often. That's it. btw, finally caught my Blue Face out swimming. As you can see he's healing nicely, no more cauliflower, and fins growing back. Oh, and as for the "goni" I have no idea what they're called. I callz 'em button polyps. They're the only kind that Angels leave alone. They're doing fine up there but they haven't really multiplied in the 4 months that I've had them.