It is OK if you feel one is not going to get the job done. I respectfully disagree with the two pump issue when some of the larger skimmers use multiple pumps. Different brand skimmers may produce different dwell times and bubble size which will attract unique pollutants. I have run two skimmers at once and have found one does most of the work. Try it out if it works well for you let us know. good luck.
Thanks Guys, Well what I want it to do was one skimmer pretty much looking after the other, so that what ever gets by the first skimmer the second skimmer may pick up.