These people have nice intentions. But your problem is the cycle. What you smell is ammonia. You have too big a bioload for that tank. You need to get a liquid test kit for ammonia, nitrites, and nitrates. http://www.aquariumadvice.com/articl...q=2&fldAuto=21 You should read up on the cycle, and you should also rehouse the koi and all but 4-5 goldfish.
-pH is not the problem, most fish can live in any stable ph from 5-9.
-Charcoal is only active for 7 days, it does not help the tank cycle.
What you should do right now is a big, 50%-75% water change. The keep up with large changes until you can confirm that the tank is cycled.