The World's first Limescale testing business card.

In many Southern African countries, limescale is a widespread issue caused by high levels of calcium and magnesium in water sources – particularly borehole water used in many homes and businesses in Zambia and Zimbabwe. Limescale may not harm health, but it reduces appliance efficiency, damages plumbing, and creates unsightly buildup. Traditional testing methods are often costly, making it difficult for customers to identify the problem early. Scalex, a siliphos-based inline water treatment device, needed a simple, affordable way to help potential customers detect limescale in their own water – while directly linking the issue to their solution. With a highly constrained budget, the original brief requested a basic educational flyer. We responded with a smarter, multifunctional alternative: a low-cost, science-based communication tool that delivered clarity, utility, and measurable impact. We created a limescale test card using red litmus paper, which changes from red to blue in the presence of alkaline substances like limescale-rich water. This simple, visual interaction gave customers immediate insight into their water quality. A colour-based call-to-action system was printed directly onto the card: a pink result (neutral) confirmed low limescale and reminded users of the benefits of clean water; a blue result indicated high limescale and directed users to contact Scalex for a filter—reinforcing the brand solution in its own signature colour. Beyond function, the card proved to be a powerful awareness tool. Distributed to 2,000 households, it drove over 650 direct enquiries and led to a 37% sales uplift in a single month. This piece transformed a budget limitation into an opportunity – creating a highly targeted, science-backed experience that made the invisible visible, turned a problem into a conversation, and delivered results that went far beyond expectations.