This article is long (5300 words) and good to read. It gives you a good base to understand zappers. And to compare to other articles too. In this area (zappers), nothing is pure true and there is a lot of research to be done and a lot of confusion to clear.
At first, Dr Clark gave its zapper on the public domain, and a very good way to use-it : The sequence 7-20.
This sequence was good because she found that big parasites had smaller ones itching them, and killing the big ones released smaller unwanted ones ones in your body. She found 5 “layers” of parasites living in parasites living in parasites, living… But 3 times 7mn was enough most of the time.
Many people found boring having to use this sequence manually (automatic sequences where rare in these times), and tried continuous zapping, with good success.
Continuous zapping is often good, but not always, and it carries its specific problems. Bigger (or longer) is not always better, even if it seems simpler….
Sometimes, the 7-20 sequence is better, specially if parasites carrying other parasites are involved..
Sometimes the 7mn doesn’t seem to be enough neither, and longer periods works better (with a rest time of 20 to 45mn in between, as usual)
Human are complex, and human problems too.
There is not a fit-for-all use of the zapper.
That's why we experiment.
You will find at least one zapper in the market, having these 3 sequences : The MZ3b
Continuous (3h) by steps (and beeps) of 21mn