What were you tanning? Krow doesn't work real well when trying to soft tan thick skinned animals. I've had success with small furbearers up to coyote size.
If tanning smaller animals and they come out hard then you probably didn't neutralize enough or didn't break the skin while it started drying. You must twist and stretch the skin as it starts to dry. When you can pull the skin and it turns white, it is ready. If it dries hard before breaking, it's too late.
You may be able to put the skin back in the tan until soft, neutralize again, then break. I'm not sure, never tried it.
As far as the product, I've had very good results with it. Hope this helps