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...
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...