Originally Posted by Kimlafeiet
Just leave the siphon end in the tank with the knob open. With the minimal amount of time it takes to get the temp on your sink correct, it shouldnt have much affect on your tank temp at all. That is how I do it with my tank with no issues. I have done it for so long now I know how much to turn the hot and cold to get it just right without much effort at all.
Best of luck to you, those Pythons really make life sooooo much easier than buckets.
That's exactly how I do it. It's easy to judge the temp by hand.....