More than likely those "weeds" did not come from the grass seed you purchased, but most likley were already in your soil or were planted by birds flying over. Some "weeds" will resprout from roots that are not killed by applications of herbicides as well as from bits and pieces of stems left behind and in contact with the soil.
The generic "contractors" grass mixes are more likely to have "weed" seeds than would those sold under a national brand name.

99% is not weed free. You can still have a bunch of weed seeds in a bag of seed. Most of the premium seed from seed companies is much lower in weed seed percentage...much lower. Check out the general lawn care board if you need advice on companies from which to buy premium quality seed. Do a search for "online seed retailers" in that board, and a thread will come up with a few trusted names.

I've used Scott's before but now I use pennington grass seed. easily available and seems to have virtually no weed seed.

Never buy Scotts or Pennington or anything you find at a big box store, hardware store or home improvement store. Never. Never. Never.

You want seed direct from Oregon, and when it comes to fescue, there are plenty of sources for it. I won't advertise them here, but you can get this year's fresh Oregon-grown fescue seed shipped to your home in less than a week. It will be 100 percent weed free. 100 percent. Do not buy from a local retailer, that is the oldest seed on the market and it contains fillers and weed seeds no matter what they claim. That's why the germination rate listed on the tag is always low compared with direct-from-Oregon seed.

If you contact me, I'll put you onto a couple of internet retailers who sell fresh fescue seed. I actually found real Houndog 6 tall fescue at a store ONCE, and it was a fluke. It was in a bag branded as Houndog, which usually contains something like Rebel or some other low germinator. Houndog 6 is a great seed. I saw Houndog 5 survive a 100-year-drought in Dixie a couple years ago and couldn't believe that browned-out stuff came back fully 50 percent after months of drougth. It came directly from the wholesaler in Oregon, the farmers, the actual source. And it was worth the $200 it cost to buy and ship it. Today, it's healthy though often flopped over, sort of like miniature pasture grass, because I don't try to manicure the lawn to look like a golf course. I prefer a more natural look.

These fescues can be cut at 1/2 inch and can look like carpet. Having another yard in Florida where summer grasses like St. Augustine and Bermuda grow faster than anywhere else, I know that almost no one mows properly. Same goes with these elite turf type fescues. They require mowing about every third day to remove 1/3rd of the leaf. If you mow once a week, you get thatch in St. Augustine or Zoysia or bermuda (less of a problem with the last one). With fescue, you don't get much thatch to speak of. Not unhealthy thatch anyway. Use a harrow during the two growing seasons and you'll air-up the soil surface fine without needing a tine dethatcher or anything like that. I actually have a small amount of fescue that is hybridized and has rhizomes and stolons. Looks like Bermuda except it stays green all winter and comes up from the soil surface sort of like St. Augustine. Not crazy about that variety, but it is part of an elite mix, so it has its place.

My favorite fescue is Bingo if you can get it. Then Houndog. Then Solara. Solara does awesome in southern heat. It can survive a Florida summer, but requires too much babying. Perennial ryegrass can be used within a fescue lawn, but again, stay away from retailer seed.

In summary, best seed to purchase will have a germination rate of higher than 85 percent, it will be blue-labeled organic or at least white-labelled 100 percent weed free with no filler. If they have it at a local retainler, don't buy it. Hit the worldwide interweb and find direct-from-the-farm seed if you can get it.

Here is a link that might be useful: Never used these guys, but here is an example

You really do get what you pay for in seed. The problem in understanding that is the way it is sold. There is a guaranteed analysis on every bag of seed. It tells you, by weight, how much of every seed is in the bag. What it does not tell you is how much the different seeds weigh. There are two invasive weed seeds where seed comes 3 million to the pound. These are practically dust particles. It is easy to get a few thousand of those in a bag. The bag will tell you, too. It might say 0.003% weed seed or other crop. Doesn't sound like very much, huh? Well 0.003% of 3 million becomes 90,000 seeds per 10-pound bag. You only need a few to germinate and you have a weedy mess.

Blanket(7b, 9b) ,

Do you still have information you can post on where one can get the fresh grass seed?