Is there any value in ultrasonically cleaning a record multiple times?

I actually A/B tested this out of curiosity. 
I filled my tank half way with Distilled H2O, alcohol, some photo flo, and a dab of surfactant and cleaned both a fairly dirty record and a fairly clean record once each so that only the outer halves of the vinyl were in the bath. I listened and - with both - it was like a wall of dirt hitting my ears when the clean part was “over.” More-so with the dirty one, but the point is you could tell on BOTH where the line fell. I then filled the bath fully, cleaned them both again so that the first half was twice-cleaned and the second half now only once. On second listening I could definitely hear again where the second cleaning ended and the single-clean began. It was not as “drastic” a change with the second bath with the cleaner record, but it definitely helped to clean them twice. I imagine diminishing returns takes over after that... 

Ultrasonic machines are certainly very good at well cleaning a record. However, IMO, the best way to clean a record is by using the Keith Monks RCM. It uses a surfactant solution brushed into the record spinning on a TT-like platter and then completely vacuums of the fluid with a German medical grade pump attached to a TT-like arm that goes over the disc one grove at a time.
This is the machine used by the Library of Congress, the BBC, Better Records and many others for several decades.
And the cleaning process only takes about a minute per side instead of 10+ minutes.

@flynnrd Nice experimental design!!!

Thanks, Flynnrd. I will be definitely be giving my problemed records a second pass.

I've been down this path. If you're only using the Ultrasonic on its own, then I would say not at all.

However, if you're using the Ultrasonic unit with a surfactant, then I would say, yes absolutely. I saw the light after reading the Audiophile Man's post on it. I tried it and it delivered a big difference in cleaning, whether new or old.

So, I've done it both ways. Using a surfactant is the way to go. And the more you do it, the better it gets. (I'm talking 2-4x; I'm not that obsessive :-). You just keep removing stuff and that helps get the stylus ever more deeper into the groove.

Hope this helps.