How to fix slurping sound of 2 minisplits + REFCO GOBI 2 condensation pumps with anti-siphon device

I had a problem on two of my mini splits on the second floor of my home. Specifically, the condensation pump (GOBI 2 by REFCO) would continue to make a very loud slurping sound every few drain cycles (i.e. every 10-20 minutes). This was very annoying and I could hear it downstairs and it was disrupting my sleep. REFCO was very helpful and told me to order an anti-siphon device by Sauermann (item number ACC00922) that only cost a few dollars. BLUF: it fixed the slurping sound immediately after I installed two of them into sections of the drain line to prevent the siphon effect that was caused by the 10+ foot vertical drop off the drain line to my ground floor. I would imagine this would apply to many different mini splits on the second floor that are using a condensation pump which requires priming of the drain line, which is interrupted if the vertical drop pulls all the fluid out of the drain due to gravity (i.e. the siphon effect).