It works pretty well. The soap apparently dissolves the aphid’s exterior. It’s kind of sad though because aphids actually look really cute. But they have a pretty big impact on leaf health. You will see hundreds of the telltale bites on the undersides of the leaves, along with little clusters of the aphids themselves. I used to use only a tablespoon of Safers in a 3 gallon sprayer every second week through the vegetating phase, avoiding the buds themselves during flowering phase, then stopped three weeks before the buds were mature and just switched to ph neutral water just at dusk after that for a “rinse”. And never any chemical insecticide for obvious reasons.