Ok, before you get slammed by JayDee...
Your CPU temp can't be 23 deg C, but I suppose you knew that
(BTW, the default warning can't be 140 deg C, it's more than likely that it would be 70 deg F, but that's too low. If it's really 140 deg C, then it won't prevent a CPU from frying)
Knowing your water temp would come in handy here.
Your question then becomes: how can I keep the same CPU temp on this new single CPU system, that I had with my dual system?
An obvious question would be: why would you want to, but hey, it's your prerogative
For a new build (assuming you're still holding on to the old system), I always recomend a heatercore, because you'll get more out of them than an expensive BIX, regardless of the model, for the same amount of money.
If you're scrapping the old system, then hold on to the BIX2.