I have purchased Zero-B around 3 years before, day before yesterday when I same the tank from inside it has become yellow and ants we there all over.
When I complained about it they are not ready to listen.they are saying they will take it back for 500 rupees. Please donot buy Zero B pristine, service guys just trying to make money, by proving me a local body for 2500.
The company is not ready to repair or get it replaced.