Not having your unit on the bench in front of me, I'm going to make an educated guess that your solution is too strong.
Not really, because a feature of that lowered resistance would also be a thicker oxide layer. His problem is his oxide layer is not thick enough.
Basically, lower resistance lowers the voltage required to reach certain oxide levels and lets you anodize *easier*. Sure, with a solution with fewer ions the current won't be as high.. but.. hrm. Suppose you're trying to push a really light car 20 miles an hour. And you're trying to go fast, and running as fast as you can, but it's not going fast enough. So your solution is kind of like saying "Well, clearly the problem is you are already running as fast as you can, so, let's add a bunch of weight to that car, so you haven't hit your top speed yet." Well, that's true. Pushing a heavy car won't let you run at your max speed. "So, problem solved, you're not being limited by your max running speed anymore!", sure.. because you can't even get it going that fast to begin with. You haven't removed the limitation, you've only made another issue so bad that *it* has become the limitation. Neither of those get your car moving above 20 miles per hour.
Kirchoff's laws. The sum of the voltage drops equals the voltage applied. The voltage applied is what he's trying to feed it. He wants as much of that on the titanium as possible. Any voltage dropped by the resistance of the solution is wasted.
The way that solution with fewer ions in it may make a difference, is in a large piece where he is getting incomplete anodizing or it's varying by area. In that case, maybe it would help to have a weaker solution. But the better test for that is to simply dip less of it at once or get a more powerful power supply.
By all means try it, but, I don't have much hope.
