I have two SP Sprayers, one is a couple years old and the other is less than a week old, and both are leaking in the same spot. Out of the bottom where the plunger is. Any ideas exactly what would need replacement. Is it common for them to develop a leak in this area? I purchased another SP Sprayer because they are highly regarded on this site, but personally I have had much better luck with my Solo. Hopefully it is a quick and simple fix, bad o-ring or something. Thanks.