You mean drain it? I just cut a T into the lowest line with a foot or so of tubing on it, just flip it over into a bucket and take out your res plug and it will drain fast, you might have to tilt your case around a little to get it all out....I usually plug the open end with a brass Fil-Port or a brass plug.Brass Fil-Port
.....1/2" Brass Plug
Man I don't know about the NB blocks for that mobo..If fitting it isn't a problem and you really need one I'd look at the little Swifty one for it, or DD has some nice ones...Waterblocks for Northbridge and Southbridge
I like to mix G11 at 10 or 11-1 with distilled, 4 ounces of this make 40 ounces of mix...Pentosin
..Then 2 drops of this for a biocide..PT Nuke
..A drop of blue "Dawn" dish-washing soap and a ounce of glycerin...The soap and glycerin are both surfactants or water wetters...Don't over use it or it will hurt temp's...The Pentosin I use just to make sure I have a base pH in my coolant, if its acidic it will be a lot more corrosive to metals then a base will...
I run my coolant down a little better in my PDF....