depends on what skimmer you are talking about. aerofoamers 8" models kick 6" models but. becket injector skimmer the most powerful skimmer 8" is better.Do a search on the web if you need more info. can't post here. But 6" skimmers are good. I chose a 6x30 then saw a 8x 24 which kicks my skimmers but same pump same skimmer.I though height was better but the 8" have more surface area that makes up for the height. But not all models,brands diy ect.. this may apply to