Port opening or no?

[3bbb7]

I have the router wpn824v3 and I am opening ports for gmod. I opened the other two that it said to on portforward.com, and then Im trying to open from 27000-27050 and when I do they dont show up on the list of opened ports. The other ones do, but it doesnt show up. I try to add it again and it says its already being used?