It sounds like you are lteting too much water through for each droplet so there is some remaining water left on the end of the nozzle which either adds to the next droplet or drops by itself. With my solenoid I normally use a 9ms opening time. Have you photographed what is happening at the nozzle tip? Ie zero delay. Also is the nozzle tip truly parallel to the water surface? It\'s possible that the drops are coming off at a slight angle? changing liquids is a pain lol I normally use coloured water or use gels on the flash hands to provide the colour. Also things like low or high fat are significantly different as well as temperatures, rinse aid etcI normally have 600mm of head above the solenoid, is your solenoid rated to operate at zero differential pressure? that might cause some inconsistencyRegards kev