Congrats on the pool!
I think the jury is out on weight loss when swimming. Personally, I have known many who have lost weight, but many who havent'. I personally did, but when I swim, it is NOT an easy, slow stroke, I swim all out for 2500 yards. I have been a daily lap swimmer for 25 years (this sept). My mom is also a daily swimmer and while she doesn't need to lose any weight, she is 75 and swims competitively. She also takes yoga, pilates and strength classes.
What swimming has done for me: ENDURANCE. No question about it, my endurance is very very high. I will not lift the most weight, or run the fastest (or swim the fastest although I would say I am faster than 90% or more of the swimmers at my YMCA)....but I will outlast just about anyone, and I'm 52. I think it has made my heart very strong. As for my mom, she DOES have some heart issues, and has had them since I was a teenager, and has had 2 laser surgeries on her heart and her cardiologist told her her heart is as strong as a bull's.
Swimming daily has made me LOVE, not dread, exercise. I HATED exercise whenever I tried doing it (in the 1970's).....never lasted long. In sept 1980 I began swimming laps and I am still at it... I added in videos and running and I just love exercise now. Swimming makes me feel coordinated, LOL (once I got over the initial all 4 limbs for themselves thing in the beginning).
It also helped me to quit smoking. The desire just went away.
In the beginning, my appetite increased, but then I wasn't an exerciser at all.....but it leveled out. I didn't gain weight though and I did lose a few.
I've never done water exercise classes but my sister teaches them and she loves it.
I would not rely on swimming alone for my exercise program because you do need land-based exercise to take advantage of gravity. But swimming *enhances* every other exercise I have ever done in the past 25 years. I love it more today than ever.
Good luck with it!
Barbara P