What plotter do you have? I have an old Ioline 4000. You will be surpised at a solution I arrived at. I plot only occasionally, so liquid ink pens tend to dry out and become useless soon. The fiber tip pens are okay, but NOT if you are plotting detailed work, because the tip flattens out...
As previously stated, the jockey pump is just for small leaks. It should be sized for less than the discharge of a head. A flow equal to a head discharge means a SERIOUS leak or, a head is actually open.
