What this step adds; in part B, the current, the gas at the plates and each doseParts already in placeA WATA-type electrochlorinator: 30 W at 12 V, 2.5 A, through 1 L of brine made with 25 g of salt per litre. At the titanium anode chloride gives up electrons as chlorine, which dissolves and meets the hydroxide made at the cathode to form sodium hypochlorite; the cathode gives off hydrogen. Faraday's law caps the yield at I × t × 70.9 / (2 × 96,485) g, 3.3 g an hour at 2.5 A, so the developer's figure of about 6 g/L after 2 hours needs 91% of the current to make chlorine: treat it as a best case. Those figures come from WATA's developer and its promoters and they disagree with each other (one source quotes 400 g/L of salt, output figures per hour and per batch conflict); this guide uses Akvopedia's 25 g/L and 6 g/L in 2 h, and models the rise as a straight line. The dosing rule used here is 1.8 mg/L: 6 mL of 6 g/L solution per 20 L jerrycan, then 30 minutes before drinking, so one batch treats about 3300 L (the developer claims 3,300–4,000 L). A cycle uses 60 Wh, about 28% of an 18 Ah battery, and gives off about 2.3 L of hydrogen. Drawn at 1 unit = 5 mm on the bench. This is a guide to how the parts go together, not engineering drawings. Chlorine gas and hydrogen come off the cell: run it outdoors or with good ventilation, away from flames. Never mix the solution with acids or vinegar, which release chlorine gas. Label the bottle, store it in the dark, keep it from children, and use it while it is fresh.