Do You Make Your Own Kefir? How?

A friend gave me some starter with instructions to filter it, save 2 TBSP of grains to start the next batch. Well I did, but it stopped working. And when I read on-line there was no mention of filtering it to save the grains. Several sites did say the stuff would just stop working.

FRiend is bringing me some more starter. Surprisingly, since he will not eat yogurt, Oban will eat Kefir. I use it, per VEt, for a probiotic for him. The INternal Specialist and our regular Vet both say it's enough for him, now he's recovered from his gut issues.

But do you filter the grains out? Do you find it stops working?

My mother used to make kefir...I don't remember her ever saying anything went awry. Then again, we never really had kefir discussions, so...