hi--i just spent half a day using a tiny old plastic pump sprayer to spray glyphosate between my lannon stone in the backyard. without getting into the political issues surrounding glyphosate (i know there are passionate emotions about it--note that i bought a generic), can someone please recommend the best device to effectively spray this stuff in a targeted manner? my right arm is aching from pumping that plastic contraption about 6 million times.

if you have a link to a sprayer, i would be eternally grateful. suffice it to say that i have several worthless sprayers sitting in my basement right now.

thank you so much in advance--

kathy