roundworm

My five month old GSD puppy has pretty much had round worm her whole life. When i got her around two to three months old i took her to the vet her first round of shots. i had a sample of her stool eval'd and was told she had round worm. i gave her the medicine she pooped out some nasty worms...

I already gave her the first deworming and a handful of those bastards came out soon after. Now for the last couple of days I've been noticing small white grains (about the size of sugar grains or sand) but no worms. My vet said she's too young to have Tapeworm in her, but what could those...