Water Still Foamy…even Effervescent like Alka-Seltzer!

I didn't read all the posts but we've had that before. It was some antifreeze still in the system. had to drain water and water heater tanks and flush lines again. if it has any sulfur smells it is bacteria. Drain sanitize and refill with filtered water. Add some drinking water chlorine to the tank, like sold at CW and Wal Mart. Don't use clothes washing bleach as it adds terrible taste to water.