don't you love when you set up your new asian made protein skimmer (jebo 520), you spend hours plumbing a recirculation mod, glue everything in place, then go to glue in the 1" pipe, and realize that they use metric plumbing sizes..I KNOW I DO!!!...so, one busted venturi valve, and $10 later for a new one, i'm back in business....just a warning to anyone whose thinking of buying this skimmer...mock up the fittings BEFORE you glue!!!