Alot of this has to do with preference. Most people thin with water or an acrylic medium or some concoction they mix up with water, medium, extender/retarder, flow improver. For basecoats and such where you want good coverage, the rule of thumb is thin to the consistancy of milk. Probably around 1:1 water

aint ratio, thin it more for layering.
What I do is mix up a dropper bottle at a time. I think they\'re 15 or 17ml bottles. Couple drops of retarder (slows drying time), 3 parts water, 1 part future floor finish (flow improver).
As for adding water to your paint pot, alot of people have to do that with their citadel pots, especially the old ones, as the lids are horrible and the paints dry out alot. I didnt use my Ice Blue for a couple months after buying it, I opened it up to use one day and found a solid block of Ice Blue paint inside. And I\'m a big guy, I mean I really crank the lids down when I\'m done. Anyway just try to keep the threads clean and the lid tight, add water when it gets thicker. But I wouldnt reccomend thinning the whole pot, just keep it at it\'s original consistency. It leaves you more options, some day you might want to use some thick from the bottle paint, ya never know.