That's why I want to measure the flow to see if it just needs to move faster. Im afraid it's moving to slow and im just losing my heat at the start of the loop. Im just not sure how much faster I can go before I stop gaining. As for supply temps there is nothing I can do with my current system. Yes I know that I can go to 180 and I'm set at 170 but it's 40 degrees outside so I try not to until it gets a little colder.