Instruct: Classify Amazon reviews into positive or negative sentiment
Query: A good product

We used this product for our house because we are on a small public water system that suffered from poor water quality (mud, rust, & misc. particles) We changed it every month.However, the water system has been taken over by a much larger public system with very clean water and we now change the filter every 2-3 months.One thing to do is look at the filter from the bottom. The filter get's dirty from the outside in and once the filter is close to all brown then we change it. Just a little practical tip.