You have air, lots of it. I had it when I bought and installed my FX5.
There are several ways of getting rid of it, firstly just try tipping the canister over a bit in all directions. Pull the hoses such that there is a constant slope from the filter to the tank with no loops, sags or turns; you need only do this for a few seconds. Ensure you have the pipes on the right way round, sounds obvious but when I started mine the very first time, I didn't and it doesn't work too well. Turn the filter off, leave for a couple of minutes then turn it back on. Check there are no parts of the hose in the tank above the waterline as if they are not sound air will get in.
If none of this works then the filter is not priming. Try removing the top and filling it with water as far as you can then try again.