Well they, like all other plants, will compete for nutrients against bad algae. However, they will not keep it at bay, like you may want to believe, any more than other plants. I noticed that mine are just as suseptable to hair algae growth. I moved them to a small nano tank and they are doing better now. They are cool algae colonies, but if you dont feel like turning them every 3-4 days then I would stay away from them.
Help control the pet population...spay or neuter people won't spay or neuter their dogs or cats!