Mervin is spot on. Too add onto Seachem Prime & Safe, buy the Safe because it's ridiculous how little of it you use each WC as compared to Prime (liquid form). 8 oz. of Safe (powder form) lasts me for 8 months (and I heavy pour it... no harm over dosing)... 8 oz Prime won't last me 2 WEEKS!
You'll find Prime in stores because stores make MUCH more since you must purchase often. Go online for Seachem Prime. I found that secret here from other people on SD. Huge $$$ saver