I'm in a remote city that barely sells any fish supplies, I can't find tap water conditioner / dechlorinator anywhere. I've got a few guppies and guppy fry on my hands now and not sure what to do. Is my best bet to use water that's been standing for a few days? I've got a tank set up - filter, thermometer. Just no tap water conditioner, and the tap water here is not the best.