I just purchased a Fluval FX6 and installed it in the tank we are putting together 2 days ago. At first it seemed to be running great (quiet and cleaning the water well), but after some hours had past, the filter started to make some slushing sounds inside the canister. When I first noticed this issue, I unplugged the filter and plugged it back in. This causes the filter to start over its cycle and it starts by purging air out of the filter. After it completed this, it started running normally again. However, its been about 10hrs since I did that, and now it is making the same sounds again.
Does anyone have any idea why it is doing this and how I can make it stop? This is the first canister filter I've ever operated, so I'm pretty novice.