I had an SWC 150 BMK (non-cone, straight cylinder) - used the same atman 2500 pump that is found on the Bubble Magus NAC 7. FWIW the SWC configuration of the same pump pulled more air than the BM unit. I was very happy with the SWC unit and for $200 brand new you couldnt go wrong.
I was then given the opportunity to test a new skimmer from my LFS. The pump pulled just as much air as the ATMAN 2500(approx 20-23scfm) but only used 13w! Thats less than half of the ATMAN. Better yet the bubble quality/production on the new skimmer was phenomenal. In the SWC i didnt get a continuous column of white bubbles -there would be pockets of water that would disrupt the bubbles making there way up the column. With that said the SWC unit still performed well.
Words only do so much - Here are some pics.
(FYI my tank is only 50 gallons - heavily stocked - sps dominant - fed two small pinches pellets daily and a 1/3 cube of frozen food - 5 gallon water change every 7-10 days and i run 75 micron socks. Nothing else is dosed except calc/alk)
SWC 150 BMK after about 7-8 days of skimming - fully dialled in;
my new skimmer;
unit was given a vinegar bath for 48hrs. Foam production pic below is 5 minutes into it being run in the sump for the first time.
24 hours later
36 hours later
4 days later (skimmer depth was changed)
wattage -
air draw
i found the best depth for the skimmer was 6" - I cleaned the cup THOROUGHLY and ran it for an entire week. During that time i changed the filter socks once and did one 5 gallon water change.
bubble action - notice how the break from fine bubbles happens low in the neck transition? Any higher and the thing over flows. Its a very powerful pump.
