Tempo run (and finally getting turns in pool right!!!)

I hate tempos. Actually I know only one person who likes them, my friend Mad. And maybe even she does not like them but at least she is good at them:)
And I think that most people do not even know what exactly tempo run means- how fast to run it. I am among those people...

Today I did 6miles including 15min tempo. I can deal with 15min tempo, right? :)
The only problem was where to run this? I knew that the trail would be in a horrible condition so I decided to see whether HS track is open, do 2 miles there, then do tempo on a road and finish 6 miles on a track.
Track was horrible but better than trail. Not plowed so I had to run through snow and because it was pretty cold there was a hard frozen layer of snow on the top. Blahhhh. Horrible, just horrible. When I got on a road at first I did not know how to run properly on a smooth surface:)
I did 15min @ 6:34 (4:06) pace (covered 2.29miles). That might have been little fast for a tempo for me, but it was only 15min, I was not doing 7miles tempo. So I hope that was ok. I am pleased with the effort.
Do you know at what pace tempos are run? Faster than 10k, slower? Or how? Does it depend on a distance?

I also did swim workout today. Main set was 6x200, 5 were reasonably fast and the last one was ALL OUT. I did it in 3:04. Well, on Monday I was not able to do 2x100 at this pace? What the heck? Do you understand it?
I have three possible explanations:
1, I took a 1min break before starting it. 1min break in a pool is like magic and you can do anything...so I was told. Seems it is true.
2, Turns. I have realized that I tend to hang out at the wall for a moment when I turn and I don't have a right technique. So today I tried hard on turns- no hesitation, bring knees to my chest and PUSH! I have a Youtube video on how to do this properly but my internet is very slow so I cannot even watch it to do it totally right... Anyway, I could really feel the difference.
3, Competition. There was a girl in a lane next to me and I knew that her warm up pace was embarrassingly close to my all-out pace. And things worked out so that she was almost at the wall when I had to start my interval. I decided not to let her pass me. And it worked! I worked hard and she did not pass me. I hope she did not mind that but I am sure that she knew I was doing send-offs and I hope she does not think that I one of THOSE annoying people.