Have you had any success eliminating your dictyota problem?
This algae is the new plague. I have personally seen it in local LFS's, online retailer pictures, and on coral frags I purchased online and locally. I am amazed but not suprized at it's ubiquitousness.
I have an outbreak myself, that I could probably have eliminated if I had known what it was when I started. The problem with this algae in smaller systems is that very little will eat it, and the fish that do eat it need large systems. The other problem is that it seems to thrive in lower nutrient high flow/high light areas.
I had a Dolabella sea hare that wouldn't eat the stuff. It eventually died (from what I assume was simple lack of food), and did not nuke the tank. It even remained in there for ~twelve hours after I realized it was dead. You definitely want to remove it if it dies as they are large creatures.
Mithrax crabs are purported to eat the stuff, but the two I purchased would rather grab at my sps polyps then do their job.
I am currently thinking about upgrading to a larger tank, in part because I can find nothing to eat it in a small one. Hopefully, something can be found, as I see this algae being very problematic in the near future for all nano-reefers and smaller reefs. When I started into this hobby over a year and a half ago, It did not seem as prevalent as it is now.
We desperately need a snail for this stuff.
One individual posted that they had success with raised magnesium levels. (the new technique used to eliminate bryopsis). Others have stated it made no difference. There are of course, many different species of dictyota as well, which makes the problem even more difficult.