I found some powder on amazon that removes ammonia,chloramine and chlorine & detoxifies nitrite and nitrates. It's called safe.. I wouldn't use this all the time, as there are some disputes whether it should be used for fish for human consumption. I would use this strictly for emergencies (ammonia spike, nitrite spike, whathaveyou,)

http://www.amazon.com/Safe-250-g-8-8-oz/dp/B0002A5WOC/

This is an 8.8 oz container of it. This stuff goes for about $11 with shipping.

I've used this for emergencies and it works. You use small amounts per gallon (1tsp per 40 gallons)