Ultrasonic LP Cleaning vs. “Thread Type” Cleaning (Keith Monks/Loricraft/etc.)

I use a Monks Omni-basically a reboot of the original Monks with some refinements, in combination with ultrasonics (like Mike, I have the KL, which has -knock wood- continued to function well though it is not new).
If I had to choose one machine, it would probably be the Monks. I do a wash cycle with different fluids depending on perceived need and a rinse step using high purity water.
The ultrasonic step adds another dimension to this which I like very much. I can use the ultrasonic alone for new records but for older grotty copies which have ground in contaminants, I find using something like AIVS #15, soaking and agitating, followed by a reagent grade water rinse, removes some distortion that ultrasonic alone did not. I encountered this several years ago on some high value collectible records, and since then, have employed a double cleaning method utilizing both.
Ultrasonic cleaning can be enhanced through the use of surfactants to lower surface tension of the water and increase cavitation effect. The biggest issue is then the removal of the surfactant after the ultrasonic process (if you are not using water alone in the ultrasonic machine). Some people are more sensitive than others to the residue left by the "cleaning" fluids-- here again, an extra rinse step helps.
If I were going to do an ultrasonic after the KL, it will likely be an industrial grade machine that is adapted for use in cleaning LPs, rather than a made for LP ultrasonic machine. This is not a cost-saving approach, though you can buy ultrasonic baths and the necessary equipment to rotate the records cheaply enough to put DIY ultrasonic into the "bargain" category. Instead, I’m looking for a more robust design, multiple frequencies, ease of cleaning the bath, filtering of the bath water for contaminants (not to filter out the surfactant), degassing and other features that tend to be associated with industrial ultrasonic equipment. The better med/tech machines, like the Elma, offer a lot of these features. The Zenith company, which builds full factory lines with multiple baths, offers a bench top (thanks, Neil!) that has an external power supply and is apparently built for industrial, not medical equipment, usage.
For what it’s worth, it is my impression that the high end community jumped on ultrasonic record cleaning largely due to convenience and got good results--many such users probably have new or pristine copies that were collected by audiophiles and ultrasonic alone may be sufficient for these. The more DIY ultrasonic approaches are less convenient than a one button "pop it in the slot and wait til the bell dings"- but offer more for someone who is crate digging and finding those jewels that need more attention. I’m not a Goodwill/Thrift Shop type record buyer, but rather someone who buys old private label and more rarefied jazz, hard rock and prog, dating back into the ’60s and earlier. Unless you find a sealed specimen (rare and has its own risks), you’ll likely encounter a record that needs some attention to achieve a high state of play.
PS: at the risk of exceeding my welcome by prolix prose, I also find that the vacuum of a record at rinse stage using the point nozzle type vacuum cleaner is more effective at removing residue and contaminants than the forced air drying typical of the "made for LP" ultrasonic cleaners. It sounds like a lot of work, but my processes have been simplified and I can roll through a stack of records in short order. I tend to clean in batches.
Oh, I had a VPI. A 16 that was converted to a 16.5 that I bought in the mid-’80s. That thing would not die. I gave it to a friend when I moved.

@mglik - I think the maintenance and care of the "traditional" Monks is overstated. When I got mine, used, I knew it was not performing as it should and had it rebuilt by the guy who does the institutional work for Monks based out of NY. He also showed me how to operate it properly and we made a few tweaks- he repositioned the "arm rest" and I added silicon washers wherever there is metal to metal contact on a screw. (Some of the old Monks show rust- frightening). Once you get the hang of it, it’s relatively easy to adjust and maintain.
I don’t use the fluid applicator head since I use a variety of fluids and I found that the dispenser flings fluid beyond the platter-- I keep a microfiber towel handy to wipe the surface as it is running, and once done, use some canned air to get water out of any crevasses, empty the waste jar, cut off the "used" thread that has been sent to the waste jar, etc. The machine wipes down easily and threading the bobbin, while not easy, is something that an owner can do with a little time and trouble- it basically involves taking the nozzle off and re-threading the "string" through the arm tube using a little rubber pipe that then allows the vacuum to pull it back through to the waste jar. You can clean a lot of records with one bobbin of the special thread.

Some of the machines may have been abused (commonly, too much waste water without emptying the jar will cause water to flow back to the diaphragm of the pump and then the diaphragm has to be replaced, if not worse). Even with a rebuild, mine came it at less than retail for a brand new Omni. The older models can be brought back to life at some cost. I would recommend that anyone buying an older Monks have it checked by someone who knows the machine. It was an ingenious sort of Rube Goldberg affair when it was first made, and has the quirkiness of a British vintage car, sans the Lucas Prince of Darkness issues.

@lewm: As @vinylshadow mentioned, these pumps are off the shelf. Monks claims theirs is specially adapted to spec from a pump commonly used in dialysis machines with a low failure rate and the ability to run continuously for a long while. If you saw how a Monks is built inside, it is really very Rube Goldberg, but quite ingenious in some ways. Part of the pride of ownership, apart from cleaning effectiveness, is the sort of quaint vintage charm of something that looks like it was put together by the Wright Brothers using canning jars inside. It is also relatively quiet. I don’t listen while I clean- the "cleaning "station" is in an adjacent room, but it is almost enjoyable to use the thing.

The cleaning expert @terry9 referred to upthread might have been Neil Antin. Neil was responsible, among other things, for developing cleaning methods to scrub 02 systems on submarines for the U.S. Navy. He is a trained engineer with a fertile mind and a deep interest in audio. He has done an extensive paper, entitled "Precision Aqueous Cleaning of Vinyl Records" on the how and why of record cleaning. It is a pretty intense read, but is well organized and takes the reader through each step, from manual cleaning and chemistry to use of chemistry in machines, including ultrasonics and covers the basics in plain English as well as more technical data that supports what he says.
I was honored to publish this paper, for which I’m happy to provide a link. No $ here for me or Neil-- labor of love. I learned a hell of a lot in publishing this and Neil is a delightful human being. Who said engineers are boring?

Too bad about Vinyl Stack- that was apparently a good product and not crazy money. 

Terry, it is a long document, so this article will take you to a link where you can download the 2nd Edition of Neil’s wonderful paper (now a tome). https://thevinylpress.com/precision-aqueous-cleaning-of-vinyl-records-2nd-edition/

@orthomead- I just want Neil to see your kind words by including him in this thread @antinn. I published the piece so I'm hardly neutral (in the interest of full disclosure) in viewing Neil's work as the most comprehensive single source of information for cleaning records. And, also for what it's worth, there is no single method or piece of equipment that I (or Neil as far as I know) advocates as a magic bullet. 
I'm glad you like the "cross-cleaning" of using both mechanical and ultrasonic. I came to that conclusion several years ago with some high value records that needed more than a pass through the ultrasonic. Ditto on final rinse step.  I treat this as a learning process, rather than claiming expertise. Neil has real expertise, and we are lucky he's also an audiophile!
best,
Bill Hart

1+ thumbs up @orthomead. I would also add that for something that may be long or more heavily contaminated, I prefer the manual or mechanical clean first anyway to get the heavy grunge out; after vacuum and rinse vacuum, then into ultrasonic for what I find is a more fine cleaning. Sometimes, on a few challenged records, it was repeating this process, with a final rinse of pure water and vacuum after ultrasonic. 
I brought a couple early UK Vertigo Swirls from send 'em back to go to copies simply by this process. And several other records that had wispy tracing distortion that I was able to eliminate through combined cleaning methods. 

@Orthomead: I first learned about Swirl due to Sabbath and have them as UK Swirls, but then descended into the vortex:
Gracious!, the Cressida albums, Patto, May Blitz, etc.

I think I have roughly 50, some duplicates, not all the super rare ones but not all of the catalog was equal in terms of music quality. Pressing quality in the era was good though and the engineering was straightforward.
Interestingly, the guy who was really responsible for launching the imprint-- Olav Wyper-- left Philips after a year or so to go to RCA. That is why I recommend the 1970 Annual as a Vertigo starter kit- 2 LPs from some of the more recherché acts. Affinity and a few others, the names of which escape me right now, were part of the catalog. And it doesn't command the price of some of the Swirls, it's almost reasonable!
One curiosity is that King Crimson’s In the Court was released as a Swirl back in the day in NZ or AUS. Never saw one in the wild. (UK release was Island Pink Label).