VPI HW-17

I have recently re-entered the analog world, and have been using the VPI HW-17, together with a Discwasher brush and fluid, to clean my albums. This does a good job, but obviously I am not using the maching to its full potential. I am hesitant to fill the reservoir, because somehow I feel the fluid will become moldy and foul, especially in the waste reservoir. Am I being paranoid? Any recommendations on how to keep things clean?