Re: prepping aquarium water

[Bill Wichers <billw at waveform_net>]

Premixing the water is a good way to get all the trace elements and other 
additives you might want to use in an even concentration in your change 
water. It also helps to give the dechlorinator a time to work fully. I'm 
not sure that that short a time is enough to get rid of all the chloramine 
(chloramine is fairly stable), but it would be enough time to remove any 
chlorine present -- especially if you put an airstone in it or use a 
venturi on the powerhead.

Most elements you would want in the water will stay put. This works like 
distilling water -- the water tends to boil off at a lower temperature than 
the rest of the stuff, so if you condense the steam you have pure water. In 
this case you lose mostly water. There are some things like chlorine that 
would prefer to be a gas and will "leave" the water over time. Some other 
compounds will break down, but this would happen in your tank too.

BTW, if you put a heater in the barrel you can bring the change water up to 
the tank temperature before dumping it in your tank. You can minimize the 
stress on your tank inhabitants that way.

         -Bill

>I was recently in a small town aquarium store. The owner was prepping water
>using a 55 gal plastic drum that had been scrubbed and washed. Had a power
>head circulating the water and had added whatever chemicals. Said he let it
>circulate for 2-3 days, and then hooked hose to the power head to load the
>water during water change. What does this activity accomplish other than
>evaporating chlorine/maybe chloramines other than what could be accomplished
>by adding a chlorine buster prior to addition of tap water during water
>change? Also, if a planted tank, would not some of the other elements
>valuable to a tap water change be evaporated out also? Thoughts? Blair

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