Wow, John. Thanks for including a pic of my tank for your bryopsis... I tried the Mg thing TWICE - with no luck.

Hindsight being 20/20. I tore the tank down, and pretty much started over. Lost just about all of my SPS in the process. Funny thing:

I added a Hiatt filtration system torpedo to my system... Look, I KNOW I didn't get rid of all the bryopsis. I KNOW it's still in my system. I can still see little tiny stems of it on my plumbing, etc. BUT, it doesn't grow. AT ALL. I REALLY think that if I'd added the Hiatt into my system before, I could have beaten the bryopsis.