Getting the dose right: neither too much nor too little

There is a stubborn belief, handed down from one generation to the next: to clean well, use plenty. An extra squirt of washing-up liquid, another capful of cleaner, a splash more just in case. The reflex comes from good intentions. It rests, however, on a mistake. Beyond a certain dose, adding product improves nothing. It often makes the result worse, while adding to the environmental impact and to the bill.

Why more does not clean more

A detergent works thanks to its surfactants, molecules that lift soiling and hold it in suspension in the water so that it can be rinsed away. There is a concentration beyond which all the accessible soiling is already dealt with. Adding further surfactants does no useful work: there is nothing left to lift.

Worse, the excess then has to be rinsed off. Overdosing leaves a residual film on surfaces: windows that keep streaks, floors that feel tacky, dishes that look dull. The reflex of adding more to compensate for those marks then makes worse the very problem it meant to solve. You enter a vicious circle: more product, more residue, more rinsing, more product.

The invisible cost of overdosing

The first cost is environmental. Any excess detergent ends up in wastewater. Treatment plants handle most of that load, but every superfluous gram adds to the pollutant load to be treated, and a fraction reaches aquatic environments. ADEME and the French water agencies regularly point out that reduction at source, meaning using less product, remains the most effective lever for limiting domestic water pollution.

The second cost is economic. Overdosing means getting through your product twice as fast. Over a year, a household that doses by eye, generously, can easily double its detergent consumption compared with an accurate dose. That is money poured, quite literally, down the sink.

The problem with dosing by eye

The root of the trouble is imprecision. With a conventional bottle, nobody really measures. You pour by sight, you press the trigger a variable number of times, you top up to be sure. The format itself does not help you dose: it encourages approximation.

Manufacturers' recommendations do exist, in small print on the back, but they are rarely followed, because they assume you measure at every use. Nobody gets out a measuring jug to clean a worktop.

The tablet: one dose, once and for all

This is where the solid format changes things. A tablet is a dose. Pre-measured, identical every time, calibrated for the right volume of water. You no longer have to estimate, to compensate, to add more. You drop a tablet into your bottle, add the stated quantity of water, and you get the right concentration every single time. Neither too much nor too little.

That simple fact removes overdosing and its consequences at a stroke: less residue on surfaces, less rinsing, less pollutant load in the water, and a consumption that matches the need exactly. Consistent dosing also guarantees a consistent result: the same product, just as effective, at every refill.

Three habits for dosing right

1. Trust the intended dose. One tablet for the stated volume of water. Resist the urge to add more: if the result is not right, the problem is almost never a shortage of product. 2. Treat marks with rinsing, not with dose. A surface that keeps a film has had too much product, not too little. The answer is a good rinse, not another squirt. 3. Adapt to the soiling, not to the anxiety. Stubborn soiling is dealt with by contact time and mechanical action (let it work, scrub), far more than by the quantity of product.

What to remember

Overdosing is a cultural reflex with no basis: beyond the useful dose, extra product does not clean, it leaves residue, pollutes water and empties your wallet. The tablet format mechanically restores common sense to the gesture: a calibrated dose, every time, for a consistent result and a reduced footprint. Cleaning well is not about using a lot. It is about using just enough.

Sources

• ADEME, dossiers *Reducing your waste and consumption* and factsheets on cleaning products. agirpourlatransition.ademe.fr
• French water agencies, campaigns on reducing domestic discharges and the impact of detergents on aquatic environments. lesagencesdeleau.fr
• UFC-Que Choisir, tests and investigations on household products and dosing practices. quechoisir.org
• Concepts of surfactants and critical micelle concentration: detergent chemistry literature (manufacturers' technical documentation and reference works).

The orders of magnitude cited refer to the publications of the bodies mentioned and should be confirmed against the primary sources before distribution.