phostrogen feed, weed & mosskiller
 

Is there a better or more user-friendly preparation available which
doesn't leave me with a blackened lawn? I've persevered with it
for a few years now, getting the measures per sq. meter right, etc.,
but I still end up with those black lines. Would it be better to just
give up on it and go back to using separate preparations for weeds,
then moss, and then fertilizer?