i use to have a berlin classic. absolutely hated it. never produced a good skimmate no matter what i did to it. i bought an octo nw150 and it outperfomed it right out of the box.
mines doin alright.
i think im gonna put an air pump PUSHING the air into the one pump that pumps into the skimmer.
i got it for 100 bucks...so i cant complain.