So this is where I will attempt to teach and educate the 3reef world on Bryopsis and how to fight it off! So what is Bryopsis exactly? It is a type of marine algae often mistaken for hair algae. It looks like a tiny fern which make it somewhat easy to identify. It can come in on frags, rock, and anything you can put into your tank. This stuff is close to impossible to rid yourself of, spreads fast, and can take over your tank! I've read many, many threads on people coming into contact with this stuff and how horrible it can get! From turning their lights of for days at a time to boiling their rocks. This algae has come back and is extremely hard to get rid off. After more researching and thanks to 3reef member 2n10, I have discovered that there is one way of ridding this algae and it works! Raising your magnesium levels to 1600ppm-1800ppm for 2-4 weeks. Now some have tried and had no success which left me feeling very worried this may take hold in my tank forever! But then it was brought to my attention that you must use a certain type of magnesium additive known as Kent's Tech-M! So again I hit the internet researching into this product and its success rate. It would appear this is the product to use and it works! Success! It is not fully understood why Tech-M works but it is believed that some unknown ingredient inside causes the Bryopsis to no longer be able to absorb nutrients. While we do this we want to have our skimmers running wet, changing our GFO and carbon weekly, feeding a little less, and also picking out as much as we can. So now that we know what Byropsis is and that we can defeat it here are the instructions and my daily diary into ridding Bryopsis from our tanks once and for all! DAY 1 So it begins. My Bryopsis algae was brought in secretly into my tank inside the skeleton of two favia frags. They did not show any sign of having the algae inside when I got them so I put them into my tank. Soon the stuff sprouted out and within a month or so started popping up in other places of my tank. So I ordered some Kent's Tech-M and got to work. You want to raise your magnesium around 90 ppm per day, not exceeding 100 ppm in 24 hours. To calculate how much to use I would suggest using this calculator on this site. Put in your water volume, which is the total amount of water in your tank not your tank size, then put in your current magnesium levels and then add 90 to that number. It will give you the amount to add in ml. With me having a about 35-40 gallons of total water volume I added 180 ml to raise my magnesium around 80-100 ppm. My starting magnesium was 1390 ppm and after adding the amount above it was raised to 1510. Which means I added a little too much. I will have to watch everything now but I hope this will not hurt anything that bad. I will update again tomorrow with more pictures and news.