Is it fine to use only that to treat tap water? It says that it removes ammonia, chloramines, and chlorine. Do you have to use it with something else to work, or is it good on it's own?
nope. its just regular dechlorinator. its fine with a test kit, and its better because it does not have any add-ins like aloe, and you can overdose up to 5x, so overdoseing isnt an issue.
i use Seachem's Prime myself and i like it. it doesn't have a bunch of added chemicals that supposedly helps fish create slime coat or reduces stress and all that. Prime helps promote a slime coat naturally. On top of that, it's your basic water conditioner and extremely concentrated. A 250mL bottle will treat 2,500 US gallons of water!
Amquel is fine and it does what it's suppose to do. Prime is just more economical since it can treat a larger amount of water compared to Amquel. For example a cap full of prime will treat 50 gallons and I think a cap full of amquel will only treat 10 gallons.