Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Been using these for years on several tanks.

I've been using Emperor 400 filters for about close to 15 years on 3 different tanks (75g, 110g, 150g).I've never had to replace one for anything other than cosmetic reasons. I was reluctant to use any cleaning chemicals.All I do is just swap out the media packs regularly, and do a complete cleaning once every year or two.Even if I get lazy with maintenance, they have great flow and really keep the water healthy.They generate a bit of splashing noise if tank gets low, so keep water topped off.And the motors hum a bit. So I don't recommend these for a bedroom tank.