The picture content is not available but looking at your zone, the grass most often confused with crabgrass is dallisgrass. When you write back, tell us where you live.

Probably is Ground Ivy, "Glechoma hederacea" and using any glyphosate product is overkill because they are very broad spectrum poisons that will kill everything they contact. Ground Ivy can be an indicator of a soil problem since they tend to want to grow. Generally Ground Ivy preferes a soil that is a bit too moist for most turf grasses and although they will grow in full sun they do prefer shady areas. Since these seed prolifically you most likely will not ever be rid of it.

Another option is Gordon Ornamec 170, it's cheaper than 2 bottles of the Bayer and will last you many years. It's also good for other tough weeds like quackgrass and dallisgrass. https://www.amazon.com/Ornamec-170-Herbicide-32-oz/dp/B008MZQE6O/ref=sr_1_1?ie=UTF8&qid=1470488280&sr=8-1&keywords=ornamec+170 Yes, you will need to apply a pre-emergent. I recommend prodiamine, it will control this and most other weeds.

What are you considering "the weed" in the picture. Is it the broadleaf plant or the yellow tipped grassy plant? The yellow tipped grass looks like the seed head on buffalo grass to me. If you are watering daily, stop that. Watering too frequently will turn a lawn yellow. Here's a picture from morpheuspa of his Kentucky bluegrass lawn versus the other KBG lawns in his neighborhood. He watered his once a week while the others watered every day. If you are currently watering every day, you'll have to wean it off of frequent watering to get up to deep and infrequent watering. I'll give you the deets on that if you want or you could look for 'deep and infrequent' in this forum.