Algae of some sort?

[ShAgMaN]

Did you use Kent Tech-M? From what I've read, no other magnesium will work....probably unintentional overdose or some other contaminate found in the Kent stuff.

I've learned turbo will eat a variety of algae if you consistently move them on to the spot YOU want them to eat.

Seahares might be a good choice, but make sure you read up on them first. They can be messy if they die.

How big is your tank? Tangs eat a lot of veggie matter which contains a lot of phosphate. So water changes will be important. Also, make sure you use good RODI water. If you get it from an LFS, test it. Some of the stores seem to go too long between filter changes.

And welcome to MAAST!

Yes, I was going to mention Kent Tech-M works great. I had a tank with bryopsis and it was the only thing that worked - along with minmial lighting and water changes.

[Ben Broyles]

I used a Salifert Magnesium test kit and then epsom salt to raise my magnesium. Of course I tested this in my 30 biocube and after weeks, it didnt seem to make a difference.
I have been reading a bit more here lately and now I have brown fuzz alge growing all over the place too. One guy said he put 40 turbos in his tank and it cleaned the place in 2 days. Of course I dont know how big his tank was and mine is a 90G. I do have a Sailfin tang that eats alot and a starry-eyed who is always eating. I do use good RODI water. I make my own so thats not an issue. I guess I might try a seahare if I can find some or more turbos. I only have 2 in there now along with like 2 astrea.