Sorry to intersect fella's, but If you're chasing a decent broadleaf weed killer that is suitable for couch, kyk, or any soft leaf buffalo then you need to use BROMOXYNIL. It's really the only herbicide that won't yellow the lawn in any way and is very fast acting. I like to apply it 2 weeks apart to ensure adaquate coverage, however, it is by the far the best herbicide I have come across for my lawn.
There are many commercial varients, but it you have a small section of lawn and don't need too much of it then there are plenty of domestic concentrates available such as Yates Buffalo Pro.
http://www.yates.com.au/products/we...dkiller-concentrate/#S2pv88YzSZKyeOkI.97
