Thanks for the reply Anton I will try one cup next time and if you find anything else let me know.I am not sure if I am having a problem with the bag because it is new.But I would like to fiqure this thing out.The first time I use it I made a mess.All the powder shot into my tank.I guess it will take some time.Could you give me an idea on how long iyt should slean a 55 gal tank after being charged?Thanks in advance.