I mesh modded mine with some plastic type scrubby "shtuff", it's called inkamat, or, something that sounds like that. I can't quite remember what it's called, it's been a few years since I got it. I zip tied it with a tiny zip tie to the top of the impeller. I've cut off the impeller tines completely and tried just plastic mesh, but, didn't work as well as just adding a small amount to what's already there. I just zip tied it to an impeller without modifying the impeller, and, for me it works very well, tons of micro bubbles.
Everyone's right in the fact that it's a garbage skimmer, unless you are up for constant monitor. I've gone 2 weeks without cleaning or adjusting it before, with 4 fish, 3 anemones, and corals in a 29 (WAY overstocked) and the skimate it produces was like thick sludge. If it's running properly, it works well. Getting it to work properly, another story. I'm too lazy to set up a sump and change skimmers, and I'm on the brink of tearing it down (for the last few years), so I keep nursing it along. It really would be best to get a different skimmer.
As for tearing it down, last week my 150 watt rena cal heater stuck "on" and cooked my tank up to 98 degrees. It killed everything exept for 3 fish, so, NOW, it's coming down. My days of red sea prism pro are over. My days with rena cal heaters are also over. My skimmer had nothing to do with cooking my tank though. Having a 55 gallon tank worth of stock, melt in a 29 gallon turned it so cloudy, I couldn't see a thing in it. Boy, did that stink, literally.
The skimmer has a v notch in the collection cup, on the right front side of it. I twist it clockwise, so, the v notch is over the return flow back to the tank. When my tank melted, the skimmer went nuts, overflowed, right back into the tank. Just another little "trick" you can do with that skimmer to prevent skimate all over your floor. It didnt' save anything in my tank, but, it kept all the "death" confined to inside the tank, not on my floor.
Bottom line, you can make it work very well. But, if you have the money, there's got to be a better one out there, but, I've never tried another HOB besides both red sea's.
reefscape15 YGPM