cyrus,

Bill is correct. Increased mag will work on some types of bryopsis. I had a type that would disappear when the mag levels where 1800-2000 mg/L. But once the levels were brought back to 1200, the algae would return.

These are some of the things that seemed to work on my 60 gallon. Most are outlined in this thread.

1) Increased mag. This really seemed to help with the stuff growing on the plastic parts in the aquarium. Constant levels are kept around 1400-1500
2) Manual removal by pulling the algae from the base instead of just "mowing" it.
3) Increased total alk @ 5meq/L, and high stabilized ph around 8.3 day and 8.2 night
4) vigorous protein skimming
5) reduced nitrates and phosphates

As long as I do the above, the bryopsis is manageable and stays at bay. But, if I let any of the above slip, it slowly returns.

I also found some little patches in my 90 gallon sps tank. I got the nitrates to almost zero, added new some phos remover, and dosed with mag. The bryopsis turned white and melted away in a few days. Haven't seen any traces of the stuff in the 90 for almost 5 months now. This could also be because of the Hiatt.

bstreep has some good advice in his previous posts and threads. I'd recommend you research his older stuff.

Best of luck to you and keep up the good fight. Don't let this stuff run you out of the hobby!