Joe G

I have a small tropical fish tank, and I have had it for about 3 ½* weeks.
I am about to clean my tank, and replace 25% of water in tank. If I use tap water, how long should I let it sit for, or is bottled water better.

Butterfly

If your using dechlor you can use it immediately. If your just going to let it set before using I recommend 24-48 hours.
Carol

0morrokh

Don't use bottled water, tap water is better for the fish as well as easier.
Buy some dechlorinator so it doesn't have to sit before use. Make sure it removes chlorine, chloramines, and heavy metals.

Gunnie

I agree. Unless you have water from the tap that is insane with ammonia or nitrates in it, go with the tap water. Make sure you treat for chloramines also if you are on city water. Some of the conditioners don't treat for chloramines so you have to be careful. Also, bottled water is usually a pretty low pH which is another reason you are better off using tap water. Your water will be more stable if you use your tap water and shouldn't stress your fish out as much.