First Partial mash oddities.

Please refer to post 17 at this link:
https://www.homebrewtalk.com/showthread.php?t=39414&page=2
Those are my notes on the partial mash recipe I made.
I have a few questions that are bothering me and I hope some of you can shed light on them for me.
1. I was surprised to see that even though I preheated my 10 gallon cooler that I had as much temp loss as I did. Is there something I can do next time to fix this problem?
2. What is the best way to recirculate the first running/sparge with a pitcher without the fear of hot side aeration?
3. Fermentation is going well, but after one day the krausen disappeared completely! I am still getting a lot of airlock activity and the brew is swirling and bubbling much like a glass of pop. There are not any signs of infection and it smells great. The starting gravity was quite high so maybe this is a reason for the krausen going away?
4. for reference when the krausen was present my temp strip read 72 at its peak. It now reads 66. Temp in the basement hasn't really changed.
Any advice will be appreciated.
Thanks in advance.

BUMP? Anyone out there?

1. No, sure. I use a 5 gal cooler and usually about a half gallon of water to preheat - this seems to works fine for me. I'd guess it's due to the 2# extra grain you used. Did you adjust your strike water temp and amount to compensate? An extra half gallon of water doesn't sound like enough without also raising the strike temp.

2. gently.
I recirc. using a pitcher - pouring it though an SS strainer that is placed as close to the mash water line as possible so that there is minimal splashing. Never had any problems w/ HSA that I could taste.

3. From my limited experience, you can't always judge too much about the progress of the fermentation from the kreausen. I've had some that fall after 2 days, and others that linger well after most airlock activity ceases.

1. I have had the same issues with my MLT, try using hotter strike water next time or do a step mash by collecting some runnings, reheating them, and adding them back to the mash.

2. I wouldn't worry about HSA from recirculating, not enough splashing is occurring for this to be a problem unless you are pouring it back in from a height.

3. Wouldn't worry about it, every brew is different.

Thanks Guys, The best thing about this forum is that you can find out WHY things are happening instead of wondering and hoping.