Hope, I have been away, sorry. . .
Please consult the maker of your zapper for instructions.
The zappers I use are all Dr Clark's. But I can say this. You can zap 24/7 if you want to. It will not hurt you. It's important to drink lots of water [wash out the debri].
Take digestive enzymes while you are zapping [immune system moves the debri to the stomach] and take Lugol'sIodine {6 drops in water} after you zap. [kills the eggs released by the dying parasites] IF ALLERGIC TO Iodine DO NOT TAKE IT, use HCL or maybe Wormwood .
It is impossible to make Colloidal Silver in distilled water unless you add salt [or some other mineral]. The silver particles need something to cling to. Spring water or tap water will do fine. Bacteria cannot grow on silver. Silver KILLS bacteria.