Being an Ex-Smoker, I used to smoke in my home. Once my kids were born, I quit smoking in the house and opted to smoke in the garage or outside. Also quit smoking in my car because of the kids. Now that I have quit smoking completely for over a year, I can say I do miss it at times, but wouldn't go back to it myself. I guess if you smoke in your home it depends on your surroundings as well as your attitude about them. However, that being said, it is a choice, wether you agree with it or not.
As far as smoking affecting tank chemistry, I have not seen anything that would lead me to believe it would be a measurable change even tho I am sure it does in some way affect the fish and the other tank inhabitants.
Just my 2 cents.
