Sorry to butt in, but the EuroReefs and ASM and Seaclones are different classes of skimmers all together!!!!!!!! EuroReefs and ASM's are basically identical expect for material quality.......IMO EuroReefs are overpriced and customer service is poor and ASM is designed the same way as the Euro's with different material, the same modifications that can be done with the EuroReef can and are done to the ASM as well.......
EuroReefs can be run externally if that is what your looking for and can be run in sump as well.....ASM are to be run in sump, but with a little know how you can run them externally...
To be totally honest both skimmers preform well, and if money isn't a factor by all means buy a Euro and hope you don't need customer service, and if your smart you'd buy a ASM or check out GEO skimmers and save yourself a few bucks and spend the extra cash elsewhere!!!!!