Here is a site with lots of info about kefir http://users.sa.chariot.net.au/~dna/kefirpage.html
Yes its normal. Separate out the grains with a slotted spoon, put the grains in a new glass jar, pour in some milk, let it sit on the counter overnight and drink it the next day after you strain out the grains. I woud give the milk that they are in now that they have been in for a month to the animals or the sink.
Kefir is easy to make.
If you don't have the grains or don't want to use them, you can simply use store bought kefir as a starter and then mix a little bit of it with fresh milk and set it out on the kitchen counter for 24 or so hours at room temp, and then you have a fresh batch of kefir.
Same thing with buttermilk.