Because I was getting ready to order another big bottle of Prime, and because I heard from others in the past that Pond Prime (made by Seachem, but listed as Water Gardens Oasis) is the more concentrated version of Prime, I wanted to check on this before making a purchase. So, I called Seachem tech support. This is the answer I got:
Seachem Prime and Pond Prime are exactly the same! However, because with ponds you are dealing with much larger surface areas, you actually don't need to use as much Prime. So, in ponds, you are actually using 1/2 the dosage you are using in aquariums, which is why it seemed like Pond Prime is more concentrated. It is not.
So, for those of you who have been using Pond Prime in your tanks at the dosage recommended on the bottle, you are actually only half dosing.