Do you have your rowing studio at home, or do you use it in a gym? And what's the name/brand? I have been running for a really long time and am hitting an age where it's getting hard on my body. Looking for what's next.
See other comments about concept2, they're the erg standard by far.
Also, consider for a moment the physics involved. Air is a fluid, just like water, and behaves in exactly the same ways. It is simply less dense and requires greater surface area to produce the same resistance. Air is also compressible and seems to produce a much more consistent stroke.
If you want the real thing, get an actual row boat and put it on a lake. Adding water to the machine does not add any degree of authenticity to the experience.