Yeah, unfortunately many chain stores are starting to carry hormoaned africans more and more. They get the fish in with the striking colors you describe, and within a month or even weeks the color will fade. It is just an easier way to sell them.
It is also getting harder and harder to find good quality africans in stores anymore. Half the time all the fish are hybrids, hormoaned, or mass bred in fish farms.
On to your question, the way I have found to get the best colors out of your africans is good water quality, frequent water changes, and a good quality food like hikari, or new life spectrum.
The best way really though is to just get a good quality fish. Nowadays, you basically have to get wild caught or f1 fish, otherwise you really don't know what the hell you are going to end up with.