Eventhough it might be cheaper to make your own dechlor, a lot of water companies now add chloramine so you would have to get rid of that also. I would just spend a little extra to buy water conditioner from your lfs. That way, you don't have to guess on how much homemade dechlor to use. The main problem is not chlorine but chloramine. Remember, chlorine can be removed by letting water sit with an airstone but chloramine will still be present. Just not worth it for me. The Doctor.