Just a quickie: If adding tap water to the aquarium via a hose, is it O.K. to add the dechlorinator as you add the water rather than premixing the whole lot. I have a cold water tank so the temperature side of things is not a problem. The filter would not be on, so am I right in thinking that if I left it a while then the chlorine would be neutralised and would not affect bio filtration? Many thanks Rufus.