"grinding/gurgling noise" I have a emperor 400 and we have same manual.
Trouble Shooting pg 22.
To quote the manual
If the emperor makes a mechanical noise..
Remove Flow Manifold, and make certin Magnetic Impeller Assembly is free to rotate. Debris may be hindering silent rotation.
Even if the product is new it still gets tossed around in a box for a few solid months though shipping and packageing causeing the Impeller to slip out of its socket then you end up with that nasty grinding noise.
Also since you mentioned its being makeing this noise for 3 days its most likely your impeller will be banged up if resocketing your impeller dosnt fix the noise should get a new one.
this is what your looking for (something like this)