If you cant tell the difference between water and biodiesel then you've got a bit of a problem. Try draining the water slowly...the difference is easily spotted.
It seems as some folk like to make a simple process as difficult as possible.
I ALWAYS drain my reactor very slowly be it glyc or water.
How am I making it difficult?
I add water with acid, pump mix, settle overnight and drain off, as yet I've not seen a clear difference between soapy glyc loaden water and wet Bio but I am a newbie to your world.
I don't use acid Jim. Just a simple, gentle, bubble system.
No pump washing until the last wash when it's a hot pump wash to reduce the soap levels to next to nothing.
No need to settle over night....not sure why you would need to do that.
I bubble overnight and drain the water off while the air pump is still running.
I always see when the water stops and the bio starts. One is watery and the other is oily.
I always wash with 10lts of water and drain that back into the measured bucket I used to put the water in with....so I know when I'm close to the mark.
I keep it simple and uncomplicated with no added chemicals....no need for additional equipment with this method.
How are you making it difficult? I really don't know