I'm in the 30ml. range I guess. I really don't keep track but I know I've been using the same Fusion for so long that I have to take a refresher course on installing cartos in tanks every time it needs another one.

JK. But seriously I have boxes of cartos I gave away because the Fusion lasts so long I figured I'd never get around to using them. I haven't bought a Fusion in a long time and still have enough to go till Christmas (1box of 5).