Does liquid aerification work?
Liquid aerification doesn't really sound like a good idea to me, but I quite honestly know nothing about it.

What I'd do: Rent an aerator, spread compost and/or some good fertilizer, and water the yard. Repeat at least once a year. If you don't have any grass growing currently, bring in some compost and mix it in with the existing soil with a tiller (or something bigger).