Aside from electrolyte, the only thing you should add to your distilled water is a pool and spa de-foaming agent. The active ingredient in these is polydimethylsiloxane. It always comes in a liquid form with the active ingredient emulsified in water and looks like a thick milky white liquid. We include some of this now in all of our kits. Add a 1/2 - 1 teaspoon per quart. It doesn't bother HHO production at all. If you see foam in your reservoir, be sure to add more until there is no foam anymore. Like electrolyte, you only need to add it once, as it will stay in the reservoir after as the water is used up making HHO. We get ours from the local hardware store and it's just called "Pool and SPA Defoamer". I'm sure specialty pool supply stores would also have it.
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