You&#x27;re thinking inside a rather small box here with the Raspberry Pi angle. Usually detecting harmful chemicals dissolved in water involves running some chemical reactions that consume their reagents, not just some reusable electronics.<p>There&#x27;s a reason the kits are like this, instead of an electronic device: <a href="http:&#x2F;&#x2F;www.amazon.com&#x2F;First-Alert-WT1-Drinking-Water&#x2F;dp&#x2F;B000FBMAVQ&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.amazon.com&#x2F;First-Alert-WT1-Drinking-Water&#x2F;dp&#x2F;B000...</a>