I just did a 100% water change yesterday, and I just went over to my tank to say hi, opened the lid for a second, and I noticed that it smells kind of bad.
It was fine yesterday, and earlier today, so I'm really confused.
The chemically adjusted water :
It is possible to chemically adjust aquarium water with the fish's natural water. It is hardly possible to approach the level of cleanliness. This is simply because of the very small volume of aquarium water.It stops bad smell from the tank which comes from water actually and also stops to spread disease in tank.