I know you may not consider it "my place" to bud in, but should you really be messing with water cooling if you don't even understand the concept of barb and fitting sizes? Also, you're trying to mix aluminum with copper blocks which supports the fact that you should probably research much more in depth before jumping into water.
Put simply, water is only for people doing extreme overclocking, pushing things so far that air can't simply handle it. (Water cooling is also significantly quieter, but that's near null with the quality of today's fans). As of yet you have not mentioned any overclocking, and I'm willing to bet your stock fans will keep everything cool.
You havn't mentioned temps yet either. Regardless, If your system isn't being kept cool with stock, I would recommend you move on up to a decent air cooling system, if that fails, there are still a variety of other solutions to your problem, and water is near last resort.
I do hope you'll reconsider.