I got tired of washing the pucks all the time so I use new ones each time. They are cheap enough and you are sure not to transfer anything from one cycle to the next. I also purchased an extra sprayer head and pump to be able to quickly change the unit out and get everything back up if any issues develop. Then I can relax and focus on changing out sprayer nozzles or cleaning the pump as necessary to fix the sprayer unit and then put this unit on the shelf. I grow 100's of clones at a time so losing a cloners worth would be very costly. yes I lose about 1 pump a year....best of luck