Not sure what to say about your family, but for the tank is there a way to cycle it through your bio filter to at least convert it to nitrate? I don't know what type of filter you have, but if you flow the water through your filter slowly before it goes into your tank, it could be enough to avoid using chemicals.
I have two hang on back bio wheels. Don't think I could manage to pour 15-20 gallons at a time through them slowly enough to give BB time to eat up 5.0+ nitrite levels.