Killing Moss on Concrete Blocks - Stain?

[DD716TED]

After living in the Pacific Northwest for a period of time I know how to kill moss in grass and when using moss killer now know to avoid getting any on concrete as it will stain it orange... BUT... I have a concrete block flower bed enclosure that is becoming covered with bright green moss...
Does anybody know a way to kill / remove this moss using a product or method that will not turn these concrete blocks orange?? Product name or ideas would be appreciated before the "Moss Monster" takes possession of our flower bed..

[tudor]

Try diluted chlorine bleach, maybe 1 part to about 8-10 parts water. Spot test first, but I'm pretty sure it will work. I've used it on sidewalks and it's fine. I 'd try to keep it off the plants though.