I am probably going to take some hits from the hardware folks with these comments but anyone taking potshots, please only do so if you have actually used the equipment (no hearsay).
Carol,
We bought the much debated Red Sea "Berlin" for our 140 reef tank. It was my husband's pride and joy and the price was (for us) not easy on the wallet. This tank has been functioning for just over a year. Most of the LR was very fresh (aquacultured over 2 years and from the ocean to me with very little layover time in the collectors tank). I house 4 erectus, two mandarins, 3 pipe fish, soft corals and extensive clean-up crew. The tank is fed heavily twice a day with frozen mysis. The skimmer was a pain to continually adjust and produced little scum
UNTIL recently. Now it is working beautifully and I have muck that would make any skimmer proud.
For the Octo tank we had an old, cheap, Odyssea skimmer that died but had functioned well enough for the price. We replaced it with a new style Odyssea and were pleased with the results until last week when the O ring seal on the pump started leaking. The O ring is a non-standard and we are not sure if it is replaceable. The leakage empties lots of micro-bubbles into the sump so we are blocking the return flow with a sponge to prevent them from entering the tank (yes, this does work). We will take it apart again this weekend to see if we can improvise a DIY solution.
Lastly, (oh boy

) we recently (several months ago) bought a, uh, ehem, Skelter hang on unit for our 15 gallon hex tank because we had a foot print problem with the CPR and I wanted a combo type hang on with overflow for this tank. The LR is several years old but I have removed the substrate and there is currently only clean-up crew in the tank. We added an air pump and wooden air stone to the bubble chamber of the unit. I get lovely scum from this setup and could not be happier with the unit for this tank!
91lxstang,
Our rather expensive Berlin went from "worst to first" (so, OK, I AM a Braves fan) over a 1 year period, our cheaper skimmers don't last the full year for comparison and our NO-NO skimmer combo works very well with a slight modification. To sum up my skimmer observations (read this as IMO), I believe that all skimmers must "season" over an extended period of time, the in-tank time and condition of the live rock are a large part of the result process and adding a wooden air stone and air supply will assist any poorly producing skimmer that is not physically broken (the hard part may be how to get the air tube in the skimmer without having to drill, with the Skelter it was easy). I also believe that throughly cleaning the
inside of the skimmer cup
funnel is a BAD idea and that allowing it to maintain a thin film actually encourages the muck to be deposited where you want it (I do throughly clean the cup itself ). I think part of the "seasoning" process is a slight build up of protein within the skimmer's central tube.