that's only if you're using 1 mill, otherwise you need more filters or you can use 1 filter, 1 retriever, and as many mills as you want
This is what i ment, Sorry for any confusion. I've not used IC in awhile, and making a watermill may only give you one now instead of the two it used to.
I typically build an array of 8. Keeps most things i need running in the beginning.