So I've been using the Citrol in the parts cleaner now for a while and I've got nothing but good to report back about this stuff.
Straight out of the 5 gal. bucket and not thinned at all, it is almost a thin, oily consistency. (A bit like brake fluid almost) I kept it this way, although 5 gal is barely enough to get the whole tank filled 4" deep. This is a problem for my pump that has a pickup screen about 6" high, so my cheap a$$ solution was to fill up 1/2 gal. milk containers with water and stuff them under the working plate! Voila.. Now fluid level high enough.
But that's the great part about this stuff too - it is sooooo non-toxic! Won't rot through plastics, etc. I use gloves while working with it but you don't really even need to do that, you'd just end up with super clean hands. The type I got has to be washed off with water after you finish and when you do that even the nastiest, greasy, oily parts come clean as a whistle.
I would highly recommend Citrol in its concentrate form like that for anyone using a parts washer / tank in your garage connected to the house. Non-toxic was one of my requirements and I thought I'd have to sacrifice strength for it but no way. The wife even loves the smell of the garage now after I'm done working with that stuff!