Beckett update,
I had to move the two skimmers to another tank as they would not skim for some reason.
Two days on the new tank and the becket is starting to skim well,
in terms of pumps required to run these things i have found that you do need a good pump to get better performance,
the via aqua 3600 is ok, but looking at the skimmer it could do with a far bigger pump.
one thing i dont like about the skimmer is that the gate valve is below the water level and the screw is starting to rust.
the deltec is not running at this stage.