hello & help

Feb 24, 2017
I am here because my 40 gallon 5+ year old tank has my whole house smelling like ammonia or bleach? had what I thought was algae (really slimy) that would grow in a matter of days on everything, but water is clear. did a 50% change for a second time in 2 weeks. same outcome. Aquarium shop said probably not algae but a bacteria. They told my to cycle API E.M. ERYTHROMYCIN™ POWDER thru it without my filters in. Day 2 complete and about to do a 25% water change on it. As of now smell is still burning our nostrils. No dead fish, plants or snails.