No it wont effect them, just use half the recommended dose its bacteria that eats algae and its safe to run with gfo, if you can scrub hair algae off and syphon it out that will speed things up
While trying to find a good spot for my torch it has broken off the plug. The flesh seems fine and the coral has opened up again, I just took the coral without the plug and stuck it into a hole within the live rock just wondering if thats ok?