Why does it work? Alum acts as a natural flocculant. Microscopic dirt particles, algae, and sediments clump together under its influence, sinking harmlessly and purifying the water above. Desert coolers, ubiquitous in northern India, benefit immensely, with pads remaining mold-free and air circulation crisp.

Public health alarms are ringing with dengue cases spiking 30% this season. Stagnant cooler water is a prime culprit, nurturing larvae that thrive in clean, still conditions. Alum disrupts this environment subtly, without harsh chemicals, providing a safer alternative to commercial larvicides.

Odor issues plague many users after just days of operation. Bacterial blooms produce that characteristic stench, but alum’s antibacterial action nips it in the bud. Families in Delhi and Rajasthan swear by the method, noting reduced allergies and better sleep in cooler, fresher rooms.

Pro tip: One thumbnail-sized alum piece suffices for standard 20-40 liter tanks. Refresh water bi-weekly, scrub interiors monthly. Avoid overdoing it—balance is key. In an era of rising utility costs, this zero-cost upgrade maximizes your cooler’s lifespan and performance.