External Skimmer help

i just hooked up an external skimmer to my new system. this is the first time i have used an external skimmer and have never seen one being used before. Its a Weipro 2020, rated for 560 gallons, i have about 200 total system gallons. My question is, how do i know its working correctly? it doesnt seem to be making as many bubbles as my old in sump skimmer, also it has a "maintain water level here" line, but thats about 8 inches from the start of the neck and the bubbles arent coming close to it at all. Is this normal, does it just take a little time to break it and then it will? any help is appreciated, thank you