Yes true, the ASM G4X is cheaper then the other mentioned above. Also it is a needlewheel skimmer if I am right and rated for aquariums up to 450g.
I want a skimmer over rated for my 180g so I will not upgrade in the future and will know that I have a good skimmer. Do you think this will be great skimmer or better that I buy another one ?
My answer sucks, but I like all four of those skimmers. I've seen or have owned them and they are all more then capable for tanks in excess of 180 gallon.
I'm a fan of recirculating needle wheels. I'd take a look at that type of skimmer from manufacturers like Deltec, Octopus, and Euroreef.
Len the recirculating needle wheels are those skimmers that can be fed from the overflow of the diplay tank or from a seperate pump, and are located outside the sump right ?
So if I am right the ASM G4X is an IN SUMP Only model right that cannot be fittef out side the sump that is why is called only NEEDLE WHEEL without the 'recirculating' ?
Needle wheels can operate in the sump as well. It's basically any needle wheel skimmer whose bubble-generating pump draws water from within the reaction body. The non-recirc types use pumps that draw water from the sump and use this same pump to generate the bubbles in the tank as well.