mysterious pool!!!

Today I happened to swim in a different pool (25 yards) due to the repair of the one I go to on a regular basis.Well, nothing seemed to be any different that usually(except of course fewer strokes per length and other related things when you switch from 25 m to 25 y.) until when I started swimming breaststroke I noticed that somehow I was swimming smoother going one way, but when going to the other end of the pool it did not feel the same.I was very confused, so I decided to time myself on one length of the pool going one way and the other.Well, i was shocked to discover that the difference in time bettween the smooth direction and the "not so smooth one"(going back) was 2 seconds!!!And I timed myself 5 times there and back to make sure i was not seeing things or something, I was swimming the same way there and back, too, by the end I even tried to swim better back, but the times still differed by around 2 seconds. That is one of the weirdest things that ever happened to me.What do you think the reason is for that? Also note: I took the same exact breaks between the lengths. P.S.I am not going back to that pool again...