OK I'm back with an update
First thing this morning my pump quit pumping, so I went back to the submersible(not submersed). And since I had the chiller drained already, I decided to take apart and clean the waterblock which actually had some deep down shit right in the center that I never cleaned out before today. It took a lot of work to get it out.
And since I had the block apart I broke out the grinder again and put 4 more channels in between the first 4 you see in the picture.
Then I decided to use the cheap Radio Shack silicone to try for a thinner layer. The AS Ceramique always ends up too thick it seems.
So the combination of all that stuff has netted me a nice improvement...even with the addition of the single GPU loop making a single pass through the chiller.
Right now the temps are better with the coolant @ -30 C, than they ever have been @ -40 or below. The temps are steadier and the coolant stays cold longer, with this slower pump, and the cleaning, and the additional modifications...ohh and thinner TIM.
I'm extremely pleased with it finally. I may try for 5Ghz again in the AM.
My repositioned probe on the block says 7 F, which is ~ -13.8 C.....lol Windows programs say 3 C, BIOS program says 0 C.