[bluespotjawfish]

Sorry, I really can't help with the buffer question, as I am a wimp when it comes to messing with pH levels. For pH I find it is best to let the tank settle in where it wants to be than to fight it. If you fight it, it may continually go up and down and once you get fish it will be stressful. 7.8 is considered normal, and since it is normal, I wouldn't add buffer. It likely won't drop when you add fish.

I think the Golden Headed Goby is pretty sensitive. My lfs talked me out of them recently. I don't know about the Prawn goby.

I just got my first new fish in my QT this week, and expect another arrival this morning from Divers Den. It's very exciting! Can't wait.