As a fellow owner of said skimmer (Got it on the cheap from a local reefer) I can say that I was initially unimpressed with the performance. I also found out that my local petco also carries it for around 120 bucks, At that price you can pick up something that is far better.
Part of the problem with this skimmer is in its design. Using a maxi-jet 1200 (older models came with the 900 I think) does not make a good replacement for a true needle wheel impeller. Maxi-Jet also doesn't yet offer a needle impeller alternative for their line of pumps, although they probably should.
If you're willing and reckless, there are a few mods that you can make to the skimmer to turn it into a "reasonably" competent skimmer. I wouldn't want to encourage something like this to a new skimmer, since there's a chance at breaking it.... but if you're brave, go for it.
Remember that your skimmer needs to "break in" and after a while, especially with this particular skimmer, you'll need to "retune it"
I'll start at the air intake. The intake itself is probably a little twisty black valve, It's garbage, it's imprecise, and it loses "tune" fairly often. It did for me at least. I would suggest you go to a LFS or hardware store and pick up something of higher quality. Something like a refrigerator line valve, or a better quality aquarium valve.
The Maxi Jet can be modified to a needle wheel-ish function. I had the most success from this particular modification. The Bio-ball mod is pretty popular with this skimmer and only requires you to be able to modify a bio-ball and the impeller slightly. There are a few tutorials online for it.
Some suggest trimming down the tube in the center chamber, the thin tube in the middle where the air enters the chamber from, is apparently too long and doesn't allow a decent amount of time between liquid and bubble contact. I'm dubious of this, but many have reported higher efficiency with this.
Others have suggested on cutting the tube in the skimmer cup as well, citing that it's too tall as well. I didn't do this mod, but food for thought.
I did do this mod.
Which allows a higher chance for the bubbles that you want to skim, to reach up higher in the neck. That's a Dr. Pepper bottle.
Make sure you seal up the joints with any plumbers tape if you have any leaks. especially around the oring where the cup and the body of the skimmer meet.
After all these tweaks and changes, I'm "reasonably" happy with my skimmate. I usually get a very dark, wet skimmate.
