I am a man in my 40s in very good shape, save for some lower ab fat. I can clearly see my upper abs, but my lower abs are behind a small handful of fat. I just bought a water rower, and my new apartment building has a gym. I have two questions:

- How often per week, and how much time per day, should I use the rower to optimize my results?
- What are the best exercises to both supplement my rowing and attack the lower ab fat?