Yes, you can buy ink and Toning Medium refills. It's time to refill when the color is no longer its full strength or when no Toning Medium comes out of the mixing chamber when you try to infuse. Refills come in 25ml bottles. Be sure to keep refills of the Toning Medium and your favorite colors on hand.
Yes, they’re replaceable, inexpensive and easy to change. How often depends on whether you are gentle with the pens or apply a lot of pressure to the nibs. The Bullet Nib is very durable and will last a long time. However the Brush Nib is super soft so for longer life, it’s important to be light handed. While the nib goes through a natural breaking in process with some small loosening of fibers on the end, if the end of the nib becomes overly frayed or if the toning medium is not infusing evenly, then it's time to replace the nib.
When infusing your Chameleon Pen, make sure that the cap is off and the nib of the marker is touching (infusing) with the Mixing Chamber nib.
Make sure you are holding the pen in a vertical position with the Mixing Chamber on top when infusing.
Wait roughly 15 seconds to start with and then try to color with this pen.