Just a quick question. Ever since i got my first fish i have always used tapwater and added dechlorinator. Is rain water safe to use without adding dechlorinator or should i add some just incase? I started collecting the water to water my bonsai because they prefer rain water and i thought it would be a good idea to use it for my fish aswell. When i was collecting it i made sure it eas coming straight out of the sky and not running off the roof.
rain water is usually pretty low in pH, i wouldnt consider it. there is the possibility of bacteria that could be in the air, and therefore in the rain, and kill your fish. if you havent had any problems with tap, why risk it with rain?
OK good thinking thanks for the advice. I have been using tao water for 3 years now and never had any problem
Rain water is generally pretty pure without much in it but in polluted areas, it can contain acids (phosphoric, carbonic, sulfuric acids, etc.) or sulfur and that sort of thing. Rain water is ideally like distilled water in that it doesn't have basically any hardness or alkalinity. Therefore, it's buffering capacity is very low, and the pH will not be stable in rain water. Rain water straight from the sky is often low in dissolved oxygen as well. That's why a heavy rain (large percent water change by nature) in a pond can suffocate the fish without good aeration.
Some people use rain water in their tanks but mixed with tap water so that they can lower the pH and/or hardness in the water. As long as you don't have acid rain where you live and collect the rain straight from the sky (no roofs, etc.), you can probably use rain water mixed with tap water. Dechlorinator is not necessary for rain water as it has no chlorine or heavy metals (with the exception in some polluted areas of mercury, what fun!). I wouldn't count on tap water to be pristine; most tap water comes from surface water that may be polluted. They monitor drinking water for a plethora of chemicals but they're only a small percent of what's out there. They don't test for everything.