Just remember a few simple things when first setting up-
Use only distilled water.
Make sure all hose connections are tight.
Test-run the water-loop with the main computer unplugged.
If things leak, it's better to find out without anything like anti-corrosion stuff in the water, and without live electronics nearby.
Fill the system, turn on the pump, and watch it- if you see a leak, unplug before it leaks too much. If no leaks, run pump for 30 minutes, minimum, to check for slow-leaks. Run a finger around all hose-connections and any screw-in fittings. If no problems, try plugging the computer in.
MUCH better to be careful, and have a minor leak, than to be overconfident, and get a doorstop. I've watercooled my system, and I gave it up simply because my expensive aluminum case wasn't big enough to fit the whole system inside- I had hoses running out the back, and moving the comp was a pain.