I'm considering investing in a python (yay no more lugging buckets back/forth). This might be a stupid question, but I was wondering what you guys with town water do as far as replacing the water goes...is it OK to fill it and then immediately add the dechlorinator? Add the correct amount of dechlorinator into the tank and then fill? I was under the impression you always had to add dechlorinator like 15 minutes before the water hits your fish. Hmm..any advice?