What chemicals are you talking about? If it's chlorine/chloramine then you'd use a product like Prime. If there are problems with sediments/heavy metals/additional chemicals, then you could run the water through a sediment filter and carbon block before using it in your aquarium.That is so funny you would say that... I swear as I was reading some of the things people wrote on here I was thinking the same exact thing!!!! WOW..... I don't know maybe I am wrong and you guys have perfect crystal clear stream water running through your water pipes and they don't add any chemicals to clean it and kill the bad stuff off, But where I live they get our water out of the muddy Maumee river and run it through 2 different water cleaning plants to clean it and then add a million and one different chemicals to it to kill any kind of micro bacteria, algae or any other living things left in the water that the filters did not get out.. And believe it or not these chemicals that are made to kill bacteria will kill it rather it is in the water treatment plant or your fish tank filter... THATS WHAT IT IS MADE TO DO... I bet you will next tell me real hot or real cold water will not kill the bacteria in your filter either right?? Now I understand why my fish love me so much and I can keep the fish that everyone else says they can't and I never have a problem with them!!!!
Not all water is created equal. You may not want to use your water directly from the tap to do a 100% water change, but that does not mean that it's a bad idea for everyone. Your previous posts imply that all 100% water changes are bad, but this one reveals that it has more to do with the quality of your source water that keeps you from doing so.