when running 2 skimmers at the same time, the more efficient skimmer will skim most of the things and the other left redundant...dun ask me y, i also dunno...hahaha...if not,only the one tat is in the best position will skim, the other will not...
but i certainly have witness this happening before...
skimmer 1: H&S (the big model)
skimmer 2: alvyfoamer 648
skimmer 3: DIY spray injector
H&S was positioned nearest to the overflow, skimmed the best...alvyfoamer and spray injector were clean after 2weeks...
but once the H&S is off, the alvyfoamer started skimming and the spray injector still clean...
alvyfoamer and H&S off, then the spray injector started...
i cannot say that alvyfoamer is lousier than H&S.. in fact, at that point of time, alvyfoamer was one of the BESTEST skimmer in SRC, if not at least on par with H&S...