Originally Posted by Alasmodified
This was very helpful also I realized I did not mean a chiller but a radiator
Aha! I had a suspicion that might be the case, but you never know
. There's really no good reason to split the loop then, just run everything in series like GingerJohn mentioned. The one rule is to put the res immediately before the pump so it is less likely to run dry, and also to aid bleeding and filling etc. Other than that, you can order your components in whichever way is the most practical or looks the best.
In my experience, the variation in water temp is usually even smaller than what GingerJohn stated--only one degree C as measured anywhere in the loop, but YMMV.
FWIW, a standard radiator/fan setup is just like standard air cooling in that you are constrained by ambient air temp--you can't go lower than that. As you've probably figured out, the term "chiller" refers to systems such as peltiers, bongs, or other refrigeration methods that actively remove heat instead of merely dispersing it.