Pre-treating your water for use in an aquarium is the preferred method. However, it is also time-consuming and usually requires the use of buckets. For faster water conditioning, you can use tap water, provided you take a few precautions. Here’s how you do it: 1. Allow your tap water to run for five minutes or so to remove any debris in your pipes. 2. Fill a glass of tap water and test it. You may want to test your tap water over a few days at different times of day to get an average. You may find that you have tap water that is dramatically different than your fish require, in which case you should not use untreated tap water directly in your aquarium. If your water is within acceptable parameters for your fish, and you want to use it directly in your fish tank, follow these steps: 1. Let the water run for a few minutes to eliminate loose debris and impurities 2. Adjust the water to the right temperature for your fish (within 2-4 degrees is usually close enough). Use a thermometer to verify the water temperature. 3. Add an instant dechlorinator/water conditioner to your aquarium. Use as much product as you need for the amount of water you are changing. If necessary, err on the side of using too much product, rather than too little. 4. Use a hose to fill your aquarium from the sink with water that is approximately the correct temperature.