Well i was looking at my saltwater tank and saw some swimming things swimming in there. It cant be any kind of bugs from outside could it? They are about 2 times the size of a baby brine. They are tiny and I dont know wat they are! Help ASAP!

Are they too small to get a photo?

Yea, They are too small. They are about the size of a bbs.

A picture of the critter would help greatly. One thing that I love about marine tanks is the amount of life that you will observe in your tank. There are little bugs, worms, crabs, snails, stars, and a bunch of micro organisms that you can't see just to name a few. My best guess would be some kind of Pod Copepod, Isopod, etc. The odds are it is harmless so don't worry too much. If you don't have a picture maybe you could give us a description of the critter.

The critter kind of looks like a amphipod. It looks kind of like a shrimp that is tiny. It swims very fast and loves to stay on the surface of the water. Some stay on the wall too. The number has double now. Guessing over 200. How did I get the pods?

Most likely came in with the LR/LS, just takes awhile for thier populations to grow
enough for you to see. I have a ton of them. Mine look liked ants to start, then grew
the long antennas and tails. Grab a magnifing glass and you will see TONS.

I had the live rocks in my tank about 5 months now and I just saw them. The tank was also running for about 8 months now.

It takes awhile for them to reach large enough numbers to where you can see them as Eznet2u said.

Are they considered a good or bad thing?

I think it is good for me since I have a scooter blenny in there with my clowns :D I was thinking of ordering some long ago but now I have them. Good thing i don't have to order anymore.