GAK!
^^^ I have circled the above. I dont know if you can see it well, but those are actual chunks of something in the cup. It looks as if the pump sucked in a fish, ground it up, and spit it into the cup almost.
But I 'revisited' the threadwheel as well. I noticed today that the arbor on the impeller for the threadwheel was a bit loose, so I tightened it. My previous tests with the threadwheel must have been with the threads slipping around the arbor of the impeller a little bit, because now, the pump can pull this...
Thats right... 1000lph!
The problem is that the added ability for the threadwheel to handle air in the flow means more water flow as well, not just more air (or more air with less water like with just making the air intake larger), and the skimmer looks like this...
The skimmer cant handle it. There is a good 100lph or so of air coming out the outlet like this. So unless the US skimmers were to be resized to handle the 60hz pump capacities (which could be up to a 50% increase in area, or from a 7" bubble plate to a 9" bubble plate, which would mean a base plate increase up to 11.5" at the base!), the threadwheel is simply out of the question. Waaay too much water flow along with all that air. Perhaps if Anton makes a custom volute like H&S, or does a face mount union w/ honed out threads on the outlet (outlet to 1-1/8" diameter is the result), and carves out the inside of the pump like a delted a little, this pump could throw 900-1000lph of air w/ just a needlewheel, but without all the water flow. Well see... but frankly, for this size, the ATB needlewheel w/ the 3/8" air intake is the best performance I have seen. I cant compare to the intended 50hz counterpart though. I wonder if I should hook up a 500lph Aquabee 2000/1 (what the 50hz ATB was designed for), maybe I can see what the 'original' was supposed to be like.
Still, I cant complain. After almost 2 weeks now, I can easily say this thing outperforms my previous skimmer. My previous skimmer had all kinds of advantages too... a 30" tall recirc with a Sicce PSK 2500 for 1200lph of air w/ pretty low turbulence (I even had a bubble 'pipe' (a 1" PVC pipe with holes in it like a bubble plate for turbulence reduction). The skimmer was also overflow fed... but it never collected crap like this thing can. The collection cups are about the same size after all, but the ATB just fills with darker, chunkier, and more. Id put this thing up against any eheim 1x1260 powered recirc skimmer. Its just a different beast. It really has me reconsidering my viewpoints on some skimming principles... rather than working all the magic with the path that the bubbles take on the way up by having a tall reaction chamber, this one seems to work more with the foam head more than anything. Beating the water into a froth, and then trapping everything in a mountain of foam... the large chunks say it all... and my previous skimmer wasnt shy in this department exactly... 1200lph of air through a 3.5" neck means alot of air flow going up through the neck... but this thing... its different. Its like its trying to prevent as much crap as possible from being lost during the draining stage in the neck. The effective interface time, dwell time, etc, of the water that is in the 'bubble mountain' is 'as long as needed' to get the crap out. I still cant get over the chunks.
And on a personal note, Anita loves not having 'big smelly' standing next to the tank anymore, and the noise is no longer a problem. This thing is pretty silent. There is a slight hum, no doubt a vibration that my glass sump is resonating... but its very mild and hardly noticable... and in my case, most likely nothing I can even blame the ATB pump for... just the way my sump is.
