Tubing- what size (ID/OD), material, maker, etc is preferred?
Fittings - What size, material, type, etc are best?
Do I need to use a thread or similar sealer on connections?
Blocks - Are blocks with acrylic components OK? What type should I avoid?
Is it true that certain metals like copper and nickel should not be in the same loop to avoid chemical reactions like oxidation?
Can all components handle pump pressure, especially radiators, without a problem? Any flow restriction issues to look out for?
Should the flow line be split before CPU, then fed to CPU and GPU, then merged back to single flow? Is that better?
How are systems filled and, more important, drained to avoid spillage?
Is there any coolant liquid better than distilled water?
All of these questions are answered in the sticky at the top of the forum.
Google is the best source to help answer questions.
Sorry, but this question is asked about 10x a week here (and this is pretty much a noob forum for watercooling...a handful of us have any idea.) Please read a little before asking questions...this is the first rule of any forum...anywhere on the web.
Please read the forum threads below and as much as you can that is linked within. Being an informed consumer will only help you in the long run when it comes to spending the couple hundred bucks.
What is your budget? What are you wanting to cool?
No problem...I am quite happy to help, but please do a lot of reading...there is a ton of information provided in those, and once you get an idea of what you need/want then it's a lot easier to help out. Wasn't trying to be gruff; I just like people to learn and grasp the concepts...it makes helping them out A LOT easier.