This stuff is waaay overly pigmented. It clogs up the nozzle on the end of the bottle, and it totally clogs up any marker you load it into. Even thinning it down 50% with dye ink it clogs up any fiber nib. I ruined three on my nibs on different markers because I wanted to be sure before I left this review. It’s in too small of a bottle to use as mop ink for that price. I guess I’ll just use it in my roller ball ones... (AP REPLY) Hi, give us a shout, we/d love to help you problem solve email@example.com. Quick note, Dr. Guts is heavily pigmented so you have to shake it well before transferring it to any container. When mixed properly the paint will be fluid and pour easily. This paint needs to in in a "pump" or action valve marker. If you put it in a mop you will need to keep it as airtight as possible as the solvent (liquid) is fast drying. Hope that helps.
This stuff is definitely different than what comes in the k60. As far as if it is the original formula? It is not but it is really close. This stuff is bomb af though so dont sleep on it, also i bought one just to fill up my markers because using this mop would be a waste of ink.