Consider the recipe of 10 stone + 100 water = 50 saline water. Sweet, it uses washing plants and is easy to get to.

Then consider the recipe of 50 stone + 200 water = 500 tar + <usable byproducts>, tar can then be used in 200 tar + 500 water = 200 saline water + <another set of useful byproducts>. That line is a bit more difficult to get to, but not very difficult.

In the first recipe, one uses 20 stone per 100 saline water.
In the second, one uses 10 stone per 100 saline water.
And in the second recipe, one gets a bunch of useful byproducts!

May i suggest that the first recipe instead gives 150 saline water? At least then all you are getting going by recipe two is a bunch of bonus products at the cost of 50 saline water. Tar is super useful as it is, leading to many other possibilities.