Hi
@Goonergal, I make lots of bone broth as my butcher sells me a carrier bag full of bones for 60p which does 3 to four lots.
Generally, roast your bones first. Yes, add marrow bone in you like.
## Whatever you put into your slow cooker, cover it, just, with water as a guide. So, don’t completely fill your pot.
I switch mine on, put in the ingredients, don’t forget cider apple vinegar, then add boiling water.
Once going , turn down low.
I start it first thing in the morning then check before I go to bed. Probably a bit manic but there you go.
If, in the morning it looks a bit watery then drain the liquid into a pan and reduce. Not found that I need to do that.
I store a lot of mine in cubes so that I can add to cooking or just make a hot drink. Quite good also just put in a pan and then some chili flakes and sliced mushroom chucked in.
Have you also a pressure cooker - it does well there.
Here is one of a myriad of recipes available on the wonder web.
http://eatdrinkpaleo.com.au/how-to-make-nutritious-beef-bone-broth/
Making ghee at present so best get on with it.