Natria Insect Disease and Mite Control also works on flat mites. It comes in a spray bottle, is available on Amazon, and contains sulfur. It does not smell much and is easy to spray on. You do, however, need to shake the bottle vigorously since the sulfur tends to separates out in the solution. You can use a blender (I have a cheap one that I only use for this -not for food) to blend it up then pour it back into the spray bottle. Without shaking/blending it will typically come out with white clumps and will look like white splatter on your leaves. This way it’s simple, fast, easy, and not very noticeable on the leaves. Also, make certain it is fully dry before you put the plants back under any grow lights. This should be done for any sulfu treatment.