Squeeky, the actual treating of the lotus was pretty successful. If the plants flowered, you'll probably get popup plants from floating seed heads for several years to come, so don't be surprised about that.
I used my boat with a 25 gal rig for the majority of the spraying, moved that same spray rig to my ATV for shallow water mop up, and now just use a Stihl backpack sprayer to kill the newly emerging shoreline plants.
I did replace the motor with a stronger 5.5 GPM pump with 1/2" quick change fittings, and built 20' and 50' hoses, with both having stainless steel adjustable spray pattern guns. The guns and fittings I got online at PW Mall, and went with stainless steel guns to keep corrosion from copper based products to a minimum. The 1/2" chem hoses and guns weren't inexpensive, but they are bullet proof, and still get heavy usage.
I also added a few oz's of blue pasture dye to each tankful. It makes it much easier to tell which plants got treated, and which didn't. I use a glyphosate, so I've got no advice on a liquid 2 4-D, but there's no need to "paint" the plants when treating. You just need to be able to visually verify the lotus plant leaf's got sprayed.
I had patches so dense, I had to wader up and pull the spray boat through all that mess. Zero lotus is there today.
