I'm trying to make a pool full of Blood-- but the "Blood" Water type looks awful; I was wondering if anyone knew any tips or settings that might make it look a little more like real blood? Or at least, not like a weird coloured liquid...

Maybe very opaque, and a very dark red with a yellowish/warm tinge to the color for fresh blood? I haven't tried it myself. If it's old blood, that's been around for a couple hours or more, the color might be closer to rust brown or it may have congealed to awful black sticky stuff. If there's a reason it would have splashed about, blood decals may be of use as well; blood pretty much stains everything it touches, if a determined person doesn't immediately make an effort to get it out.

Otherwise, try looking up blood effects in movies and trying to copy them. Most blood in movies is actually corn syrup with red dye, but more people base their concept of what blood looks like on these effects rather than on actually seeing blood in copious quantities.