It does sound like hairballs.

I have both problems with Ripley. He eats too much to fast and throws up and then sometimes he throws up hairballs. The first time I saw one I thought it was poo too but my husband who grew up with cats had to explain. I think they should be called hair logs or something more descriptive. Never are they in a ball form.

Anyway, to help control the hairballs try brushing your cats regularly. We've been brushing Ripley nightly for years now and he rarely has hairballs any more.

Also, could your older cat be grooming and licking on your other cat? That could account for the all the hairballs all of the sudden.

Good luck.