Yes, from what I've read on this forum you can use Prime. I believe that Prime turns the ammonia into ammonium, which is not toxic to fish, but will still support the bacteria that converts ammonia to nitraites.
As an aside, if your
pH is below 7, you don't get ammonia in your water, you get ammonium instead. I believe ammonia is NH4 and Ammonium
NH3 (I may have that backward). If you have an
API Master
test kit you will see at the top of the ammonia card it says NH3/NH4, since depending on your ph you could have one or the other.
You do not want to use a product such as Cycle or AmmoLoc (I think that's the name). They somehow lock up the ammonia and it becomes unavailable to the benificial bacteria and starve that bacteria out. In such a case your thank will never cycle.