Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Here is what I would do:
1) Get a test that tests chlorine and ammonia.
2) Test the tap water when you are ready to do something.
3) Add the right amount of Prime to handle the amount of chlorine and ammonia in the tap water. My tap water tests 1 ppm chlorine and 1 ppm ammonia from chloramine. A single dose of Prime takes care of it almost instantly. No need to wait just for dechlorinating. But with variable amounts in the water TEST EVERY TIME. Read the label. Prime can be dosed at higher amounts to handle different levels of chloramine. (Pretty much any dechlor will say how much chlorine and ammonia it will handle at what dose)
If you want to do water prep in a garbage can that is just fine, see below for the set up, but it does not have to be done a week ahead. Half an hour is just fine.
If you want to store water in jugs or bottles I would leave it as it comes out of the tap with chlorine or chloramine to minimize the bacteria growth. No dechlor until right before you are ready to use it, then allow half an hour or so. Not because the dechlor takes half an hour, but to allow gas exchange.
Pour the water into a larger container (garbage can, 5 gallon bucket, whatever). Dose a dechlor that handles chloramine as needed (TEST). Run an air pump or fountain pump set up to flume the water. Flume is when the pump (air or water pump) is set in the middle of the garbage can and is aimed vertically. The water from the bottom of the can rises in the middle, spreads out at the surface (allowing optimum gas exchange) then sinks along the outside as more water rises. I have found half an hour of this will provide very good gas exchange, so the water gets well aerated. You can dose the dechlor, then run the pump (air or water) for a few minutes then test again for chlorine and ammonia.
Make sure the test kit you are using is compatible with the dechlor you are using. You can get false readings when you are using the wrong products.
If there are other issues, not just chlorine or chloramine, then there may be a reason for preparing the water ahead of time and allowing more time for treating it. You could...
...Get a filter designed for household use to treat the water. This might be something like an RO filter or other. There are portable RO filters that you could store in the same garbage can that you use to prep the water. Use it once a week, do the water change, then put it away.
...Set up some other method of treating your water, for example getting whatever resin pillows your water needs from fish stores or on line. There are pads for removing all sorts of things like copper, phosphate, water softening pillows and MANY more. They tend to be pretty expensive, and many are one-use items. They get filled with what they are supposed to remove and then you toss them. Anyway, put these in a canister filter and run that on the garbage can of water for several days to a week and see if that does what you need. But you need to know ahead of time what is in the water and what you want the final numbers to look like.
With chloramine, for example: The test I have actually tests chlorine. I also have the ammonia test. When I use the dechlor the chloramine is broken down, and the chlorine and ammonia are locked up. First test (tap water) shows 1 ppm ammonia and 1 ppm chlorine. Second test (after dechlor) shows no ammonia or chlorine. If I under-dose, then the second test shows some chlorine and ammonia. So I add more dechlor.
If you are having problems with directly filling your aquarium from the tap there may be something else going on, not just chloramine problems.
Fill whatever container you need to do a water change (I will keep calling it a garbage can). Add dechlor. Flume for a minimum of half an hour. Then do the water change.
If this solved the problem, then I can make an assumption: The tap water is either too rich in gas, or too low in gas (meaning air; nitrogen, oxygen and CO2). Circulating the water in the garbage can makes the gas in the water become in equilibrium with the air, which is what the water is like in the aquarium. Less stress to the fish when the new water is as much like the old water as possible.