dont know yet im buying one this week. Im looking at the Duraflo 5800 (i think thats the name) or a shurflo. Or an x-jet but I'd rather have the control of the low pressure on a ladder. My only prob is how to rinse the green spots off after the chem. application if I cant get close on the ladder. or maybe I can do it with a garden hose, I've only done a few roofs last summer and most were walkable. You have any suggestions on a roof like this (unwalkable and far away from the gutters)?