I have a Lesco 200 gal compact sprayer. I was wondering from anyone who has one of these how often you change the pump oil. At least that is what I think it is? There is a small master cylinder container with a red cap. If that is not what it is please do tell me....What kind of oil you use and how do you change it. I have the rest of the system mastered.......just very unsure of the pump oil and the Lesco people don't know either...at least the rep that sold it to us didn't and didn't offer to find out. Thanks for your help in advance.