Klaudio ultrasonic cleaner - Only using distilled water?

Holy Water .... improved Headroom

Fellow enthusiast Rushton has published in Positive Feedback, here on the Analog Forum, and again on Vinyl Asylum, that he is using a home-made ultrasonic cleaner and his bath contains isopropanol and a nonionic detergent, diluted in distilled, deionized water.  If you want his opinion and experiences, you may want to find his threads or his article.  Without having done it, my personal opinion would be that adding at least a low concentration of nonionic detergent should be advantageous, because it reduces the surface tension of water, thereby allowing it to penetrate further into the grooves, and the detergent effect also should help in solubilizing crud.  (I am not sure why you want to restrict responses to those using Klaudio, but I do apologize if you find Rushton's work to be irrelevant on that basis. I found it interesting, because in almost all other cases, including yours, ultrasonic cleaning is done with "pure" water, if not holy.)

Only distilled water

tried expensive Nerl reagent water
no need

I prefer to restrict responses to those using Klaudio machines simply because the Klaudio machine is a one-step process. You drop in the record, the Klaudio machine does all the work, and you can play (or sleeve) the record as soon as the cycle is complete. The DIY units require the user to make a decision after the ultrasonic bath -"Now what? Do I need to rinse? Do I vacuum? Do I air dry?" I wouldn't be interested in any additives or detergents that require an additional step.

Yeah, sometimes I'll do a "pre-clean" using DiscDoctor brushes and MoFi Enzyme Plus solution. Those are mostly used LPs that need some extra love (lots of visible crap, finger prints, smoke smell, etc.). If I did marathon cleaning sessions of used LPs, a Spin Clean as a pre-treatment wouldn't be a bad idea.

I have been using reagent water. Perhaps unnecessary, Rush mentioned a fairly high grade of water he gets at Whole Foods for almost nothing (you bring your own container). I still use the reagent water to mix fluids (Hannl fluid is great on my Monks) and to do rinse steps. I pre clean all used vinyl on the Monks before it goes into the KL. If a new record (I buy some, not many) looks grotty out of the sleeve, it gets pre-cleaned as well before I plop into the KL.
The more interesting question --can one use some kind of surfactant in the KL? I don't think it is authorized, and am not suggesting that anyone do it, but the more I learn about US, the more I find that the commercial "audiophile" machines don't do it all--that DIY is probably the way to go- not just to save money, but theoretically, to optimize cleaning. 

Using distilled water prevents calcium build up.  Only use distilled water.

This six years old thread has calcium buildup!