Wry interesting- I’ll have to experiment with that!!I actually had to stir the soap through the water then it would just vibrate. No-to very little suds at all. more when your took the tray out and did a scrub. I put a "healthy" dose of soap in and added more ad-hoc. More/Less soap making little difference with a preference for more....even with lots there was no "suds" issue
Thanks!