The speed stir not only makes it way simpler, and improves accuracy/consistency, but it's also backlit and you can see the drops falling into the vial if its dark. Jussayin.this mom is using her flashlight to count r-0871 drops in any case.

It's the best $48 one can spend on their pool IMO. (Assumimg there already is a reliable test kit, of course).
Or bring the sample inside with or without the speed stir. You still WANT the speed stir tho.