People have been doing it that way for years. Google "ammonia surfactants" and you'll find threads all over the place where people panic because they used the wrong ammonia and had to tear down their tank and scrub it down. You'll find a few threads of mine in there as well.
Just to cover all of that, all soaps are surfactants. Not all surfactants are soaps. Surfactants cause a liquid to spread out, basically breaking the surface tension. Think of a drop of water on glass, it beads up. Surfactants reduce this effect.
If you buy the Target or Wal-Mart brand of ammonia, it will say "pure ammonia" or something like that, then the label will list "surfactant". When you shake that stuff up, it will get a little foamy at the top but the bubbles will break right away. This is not a soap-based surfactant and is generally safe to use (and I did, at first). Find another bottle and shake it up and if it
stays foamy at the top, like you would expect would happen if you shake soapy water in a bottle, then that stuff will ruin everything in your tank, and you will have to throw out all decor and plumbing, and bleach the tank down. Don't use that stuff
The Ace Hardware brand is slightly more expensive but is also 2x the strength and does not list surfactant as an ingredient, so you can be assured that it is 100% safe. I would not buy anything but that stuff. Seed your tank with bio-media, dose about 1/8 cup and test it an hour later. Keep dosing until you get your ammonia above 1.0ppm and keep in there, but don't go over 4ppm or the biological process can stop. I tried to keep it right around 1.0 or maybe 2.0, testing before and after dosing and keeping a log book.