When I first set off to battle bryopsis I had the impression just raising the Mg levels would be sufficient. After raising the Mg to around 1750 using the standard 2-part mix and waiting a couple of weeks I decided to give up in this approach.
I did some further reading and found that it wasn’t just about bringing the Mg levels up but about using Tech-M to bring the levels up to about 1600, so, I decided to give it another try. Through water changes I got my Mg back down around 1500 and using Tech-M brought the Mg level up to 1600 and waited a couple days but there was no change in the bryopsis. Tried 1650, still nothing, I even brought Mg up to 1700 and even after another two weeks, still nothing appeared to be happening. At best it may have slowed down the growth but the algae looked as healthy as ever.
Not giving up yet I posted a thread on the subject looking for additional information with the idea that it may not just be the elevated level of Mg but rather the concentration of whatever is in Tech-M that seemed to be doing the trick. Generally what I found out is that most people started around 1400+/- and raised it to 1600 or about a 12% to 15% increase using the Tech-M product. Using this new data point I further raised the level to 1750 using Tech-M, or a 13% increase from the 1500, and within a couple days I started seeing results, Bingo, it very well may be a concentration of the Tech-M product versus elevated levels. I ended up bringing the Mg level up to 1800 and zapped the stuff.
Side notes – Mg over 1650 will significantly impact your snail population; I lost over 80% of my astrea snails and at least 20% of all others.
Suggested approach:
Drop Mg to as low as you can withstand without stressing corals and use Tech-M (or other proven product that have a different make up then standard 2-part) and raise your Mg level by 15%
