Armegedon??

[SALNYG]

I bought a new thermometer, and test kit. After my water change the Nitrates were at 80, ill plan to do another WC this week. I'm going to take the opportunity to re-do my set up starting with my substrate (gravel to sand), and possibly redo my filter. I currently have a fluval canister but for the past 6-8months have been getting these tiny little bubbles - from the side it almost looks like the water is a little cloudy- but it's actually the bubbles; I'm wondering if its the filter? Thanks again for your help/insights - please feel free to pass along any in regards the the above as well.