HighlandReefer posted this on RC:

 

"...Good questions. No research to back any methods used by hobbyists to control bryopsis. We really don't know what kills the bryopsis and can only guess logically.

For example, lets say that it is the heavy metal contaminates in the Tech M that is responsible. The most likely is copper. However, research has shown that when you mix heavy metals like copper and lead or copper and zinc, the combination of the two (perhaps more) will kill algae at lower doses than either of the two metals independently (A synergistic effect).

If it is the heavy metals or their combinations then your current heavy metal level in your tank water can influence the amount you need to add to get to the control level. The little research in reef tanks has shown that copper can vary from undetectable to over 30 ppb in hobbyists tanks. Copper levels over 30 ppb can cause problems (perhaps the most likely zone to kill bryopsis) and levels over say 70 ppb can kill invertebrates. The problem is how much do you add since we can't measure heavy metals in reef tanks with hobby grade kits. What are the levels that kill byopsis? What are the heavy metal levels in Tech M? The dissolved organic levels in your tank water can influence the results as well, since heavy metals can quickly tie to them and toxicity is reduced in the organic form vs. the inorganic ionic forms. There are a lot of factors that can interfere with this process of control given it is the heavy metals.

That said, from reading through the threads, it seems that an increase of 300-400 ppm magnesium using Tech M works best. You will want to increase the mag as quickly as possible without killing other things. It is recommended to not increase mag by more than 100 ppm per day due to the contaminates. Perhaps somewhere between 50 ppm to 100 ppm mag increase is the ticket. Hobbyists have reported the loss of snails and shrimp when doing this, so you may want to remove any before trying this. "

 

As far as dosing up to 3200ppm...that's insane...and I don't believe it.  Raising up to 3200 over a day would shock everything.  My hubby accidentally dosed a gallon of magnesium to our 40g aquarium several years back instead of what he thought was RO/DI topoff water.  Lemme tell ya, I lost about everything.  I'm going to take a stab in the dark and guess maybe that guy's test kit was off or he didn't know how to measure (or just liked to make stuff up.)

 

 

The thing is, is that everything is toxic at some level...different levels for different things.  What is toxic to algae may require more of that "toxin" for higher order animals.  And, there are different ways to uptake toxins, and that may play into this as well.  I'm not arguing it's copper, I'm just arguing that what is killing the bryopsis is probably also lethal to other things in our aquarium (which is why people have problems with higher doses) just not at the 1600ppm magnesium level.