As mentioned in an earlier post, I have a Happybuy ultrasonic. This is a somewhat similar design and price point. From what I've gathered thru the years, it's best to space the records so there's roughly a 1" spacing between them. This spacing in theory makes for a more efficient and thorough ultrasonic cleaning process for each individual record.. Bottom line, although I could stack 6 or possibly even eight records together for one cleaning cycle, I only choose to clean 3 in one cycle. This leaves a generous 1"+ spacing between the records. I clean 30-36 records per session using this method and I'm pleased with the results. Needless to say, a new batch of cleaning solution is mixed for the next session. FWIW, the final step in a session is a distilled water rinse and vac with a Nitty Gritty.