skimmer

[Taff]

hi guys hope you all had a great new year,

I was just wondering if anyone knew of a good website or have themselves
instructions to build a skimmer? downdraught or air driven, i have one
outlet from tank to sump through a 50mm hole in base of tank is this enough
to run through skimmer and keep the water flow running, i have a large pump
but not sure of the size,
cheers big ears

Taff