Hi Ben, welcome to the tank.
Do you have live plants in your tank? Reason I ask is live plants provide a cushion for overstocking. Regardless, a golden gourami gets too big for a ten gallon, try a dwarf if your heart is set on gouramis. They come in many colors.
You are overstocked as is.
You can filter with peatmoss to lower your pH naturally. What is your pH now?
Some LFS's will allow you to trade in your fish for store credit, or they will just take them off your hands. Most of the franchises don't do that, so look into the small, fish only stores. If that doesn't work, take out a free ad in the paper for your fish.
If you don't have live plants, maybe you should consider downsizing... Drop the cardinal school down to seven, cut the phantom number in half, and maybe add another cory.
However, if you like a crowded tank, I highly recommend planting heavily with live plants. Check out our plant section for more info.