Waste of money. If you're going to do custom water cooling you want to be spending hundreds of dollars on it. That's why closed loop implementations are often satisfactory for 90% of users.
If you have the money and will to implement an open water loop, look at brands such as EK, XSPC, Koolance, etc whose products are decent and reliable.
Yeah, stick with the well known brands, personally, if you're looking to get into an open loop system that you can expand on later, buy the xspc raystorm kit with the d5 pump