24 support a nozzle carriage 26 which with the slide members 24 is slidably movable lengthwise of the tank 10 on the rails 18 the slide members 24 are provided with cylindrically shaped bores 25 extending there through and in which are disposed the rails 18 such that the slide members 24 slide along the rails 18 the nozzle carriage 26 supports a water delivery pipe 28 which extends downwardly toward the bottom 14 of the tank 10 the water delivery pipe 28 also extends upwardly from the nozzle carriage 26 and is connected to a flexible water delivery hose 30 on which there is mounted a water pressure regulator 32 which in turn is in communication with a flexible water source hose 34 the lengthwise rails 18 are mounted on lengthwise upper edges 42 of the side walls 12 of the tank 10 the slide members 24 are mounted respectively proximate the upper edges 42 of the tank side walls 12 and are movable along the rails 18 the nozzle carriage 26 is slidably mounted on rails 46 which extend widthwise between the slide members 24 thus the nozzle carriage 26 is movable on rails 18 46 lengthwise and widthwise of the tank 10 on the bottom 14 of the tank 10 there is disposed a test slide mount assembly 48 for receiving and retaining a test slide 50 which may be mounted for testing of the adhesive strengths of the biofilms on the slide and.