I don't tend to dilute my stock/broth unless it tastes really strong. I use all the broth for one pot of soup and then I end up with lots of soup to freeze! Just skim off the fat, then add veggies, etc. to the gelled broth. It will de-gel as it is heated.

Just use however much broth you need to make enough soup to feed people, if you don't want to make a big batch of soup. You can freeze any leftover broth and use it for another batch of soup down the line.