It's practicly impossible to filter out single celled floating algae, they are just too small, so you'll likely be dissapointed if you skip the UV and just go with a skippy, unless of course your pond naturally starts clearing up on it's own, in which case you'll give credit to the skippy. (Am I starting to sound like Waterbug? At least I didn't say they are "worthless".)
Let's be fair...I think the combo submerged filters for sale to the mass market are worthless. Skippy filters are better because they're larger, so I would only consider them "almost worthless". In a pond with a large fish load, OK, I'd call Skippy completely worthless.
But what I think of Skippy or even whether it works or not, or how well it works compared to other filters has never been the point for the Water Garden hobby has it? Don't read about a lot of testing, or any interest in tests for that matter.
Buck, as Mucky said, you've had your pond awhile now, it'll take you a few more weeks to build the Skippy...I would say there's every chance your pond will clear sometime within a few months after adding the Skippy. And the Skippy will be hailed as the cure. That's win-win. Your pond is clear and you can feel good about building the Skippy. Sure outside of Water Gardening the Skippy long ago was replaced by better filters. But that dismisses the real importance of Skippy as a self esteem booster which it is seriously very effective. And why do we have Water Gardens...to make ourselves feel better. That's the purpose of any hobby.
There are lots of fish keeping endeavors that are technical. Reef aquariums, fish farming, high end Koi ponds, etc. These all need to be technically proficient or their fish die really fast. Water Gardens are entirely different. You can throw just about anything at a Water Garden and it's just going to keep plugging away. Few fish die, no problem, $1 worth of feeder fish and the pond is back in business. Just read a post where a person was sending their home's grey water into their pond...perfectly OK for a Water Garden.
Yes a UV will clear water in 3-5 days 100% of the time if sized and installed correctly. But is that really all that important? Doesn't that kind of feel like cheating? And besides, it seem like most people don't even install them correctly so really, they don't work that well in Water Gardens.
So the bottom line is don't sweat the details. Build a Skippy if you'd enjoy that. You'll probably see clearer water at some point and be very happy. I enjoy building filters, built maybe 50 in my day. It's a hobby...enjoy.