I ran the larger model for a few months and personally thought these skimmers really did a super job,...as was stated in a previous post,..the micro bubbles lasted for a day or so until the saltwater slime built up and then she really started to kick butt,...the adjustments are accomplished by slightly turning the plastic pipe located above the outlet flow,... Turning it slightly either left or right will raise or lower the water in the collection cup,....
IMO they're a great bang for the buck,....I'd still be using mine but I wanted to get a larger skimmer and to eliminate the
HOB situation,....Dary