I myself have started to get a diatom boom in my tank. I haven't tried removing it personally, I've hoped that it would go away. But I've waited about 4 days now and it is still there (on decorations, glass and blotches on sand)
When I get home today, I'll remove them with a sponge or I'll syphon as much as I can up. I first started to get this boom when I went to London last week, I think my mother, who was looking after the tank, forgot to turn the lights of, or only turned them off a few hours a day. In addition, just before I left to London, I took out my Hornwort, so it could be a case of both things.
When I get home and clean it out, and it comes back again, how else could I get rid of it?
My tank is only 3 weeks old.
Addenda: I can't be the tap water, because my previous tank was filled with the same water and I never had a diatom boom.