When you are doing a water change with babies in the tank, just be careful to keep the siphon low, almost to the gravel, and don't move it around much. Our LFS
is notorious for having ich. They have a great selection, and great prices... so I keep going back... I have however learned the benefit of a quarantine tank!
When I get ich in my 10g tank, I usually up the temp to about 80 and add aquarium salt to the filter gradually. I start with a spoonful of salt, then work up to a total of about 4 tsp over the course of several days.
I tend to prefer bottom feeders (dojos, cat fish, plecos, etc), so my experience is somewhat limited... but I do know that if your water quality is bad, its a death sentence to all your fishies! The sooner you do something to improve the conditions, the more of them you can save. You might also try adding some Stress Coat to your tank. I've found it to be very helpful