Don't worry about adjusting your ph, most fish are tank raised and were probably housed in water fairly close to your own. Acclimate them properly when you bring them home and most will be OK in the water you have.
Algae is usually the result of too much light or direct sunlight. These first two things are minor and no real reason to completely clean tank and start over.
Gourami's can be aggressive if you have two males, they're a breeding pair, or a combination of these things in too small of a tank. I have 3 sunset honey gourami in my community tank, and they're commonly kept in community tanks with other fish.
Again were glad to help but need information. Did you cycle your tank? How big it? What fish did you try?
Not trying to be mean but lfs (local fish stores) are bad about selling anything and giving poor advice.
Here is a thread on getting started, the nitrogen cycle and other useful information.
http://www.aquariumadvice.com/forums/showthread.php?t=154837