Bryopsis Thread Summary
Here's an attempt to summarize the findings in this thread for those who don't have time to read all 50+ pages. This is meant as a reference for those who are battling bryopsis and want a summary of what's been working for others. The main observation is that bryopsis can be effectively killed using magnesium supplementation with Kent Tech-M, Epsom salt, or certain other magnesium supplements. Many thanks to TWallace, jdieck, redfishsc, and everyone else for contributing so much to this thread. It's been a lifesaver for me and my tank.
Effective Ingredient
(1) Magnesium -- The thread started with TWallace's posting that elevated magnesium levels were effective in killing bryopsis. He noted his own success with using Kent Tech-M to elevate magnesium levels from NSW levels (~1300 ppm) to nearly 1700 ppm. However, subsequently many have questioned whether it is the magnesium that's responsible for killing the bryopsis. Several people chronicled attempts to dose magnesium through MagFlake (Magnesium Chloride/MgCl2), which did not result in the bryopsis dying, even at Mg levels in excess of 1800 ppm (however, at least a couple of people have reported success dosing magnesium with MgCl2). Rightly or wrongly, a clear majority of posters seem to believe that magnesium by itself is not getting results, but that Tech-M should be used in preference to other magnesium supplements. However, others have also noted success with Epsom Salt (Magnesium Sulphate/MgSO4) and certain other commercial Mg supplements. Also note that Tech-M itself apparently is made using both MgCl2 and MgSO4.
(2) Tech-M "Secret Ingredient" -- Because more people have reported success dosing Kent Tech-M than other forms of magnesium, there's a theory that Tech-M contains some other herbicide that's responsible for killing bryopsis. Lots of speculation of what this might be. Kent claims that Tech-M contains only a mix of "pure grade" Magnesium Chloride, Magnesium Sulphate, and RO/DI water (along with trace amounts of impurities such as copper). It's possible that Kent's source for "pure grade" MgCl2 and MgSO4 contains a key impurity that affects bryopsis.
(3) Copper -- Some believe that copper is the "secret" ingredient in Tech-M that's effective for bryopsis. Copper is a known herbicide and at least certain formulations of Tech-M are known to contain copper. However, it's unclear whether there's enough copper in Tech-M to work as a herbicide (Tech-M is believed to contain only trace amounts of copper as an impurity, although potentially in higher concentrations than NSW).
(4) Sulfate -- An alternative theory is that the sulfate in Tech-M and Epsom salt is what causes bryopsis to die. Several people have reported good results dosing Epsom salt instead of Tech-M.
Application Methods
(1) Slow Increase -- One method of using Tech-M/magnesium is to slowly raise the magnesium level (by less than 100 ppm per day) in the tank and then letting the tank "stew" by not doing any water changes for a period of weeks while the bryopsis dies off. Some people have reported apparent eradication after as little as two weeks. Others have reported needing longer periods.
(2) "Shock and Awe" -- Another method people have used is to dose Tech-M/magnesium to quickly increase magnesium levels (by ~100 ppm per day). Some think this is more effective than the slow increase at killing bryopsis. Even this method has been said to involve maintaining extended periods of elevated Mg levels (months).
(3) Basting -- Yet another method people have described is using a turkey baster or syringe to spot treat bryopsis with concentrated Tech-M, with circulation pumps off. The theory is that if Tech-M contains a herbicide other than Mg then basting the bryopsis avoids the need to waste Tech-M and unnecessarily elevate Mg levels.
(4) Long Term Daily Dosing -- Others have reported that it was necessary to dose smaller amounts of Tech-M (~1 ml/gallon) over a longer period of time. The theory behind this is that the herbicide in Tech-M/magnesium supplements lasts only a short period in the tank before it's organically bound and skimmed out and therefore needs to be replenished on a regular basis.
(5) Additional Treatment -- In addition to using Tech-M/magnesium, people have suggested that the magnesium treatment is more effective when (i) keeping elevated pH levels (>=8.5); (ii) exposing the bryopsis to intense light (based on observations that bryopsis in high light areas of the tank dies faster than elsewhere); (iii) NOT running carbon (on theory that it adsorbs active herbicide); (iv) manually removing bryopsis from the tank (both before, during, and after dosing); (v) using a turkey baster to blow out detritus collected within the clumps of bryopsis; (vi) elevating alkalinity (to > 9 dkH); (vii) overskimming/skimming wet; (viii) running a phosban reactor.
Adverse Effects
(1) Many people have reported that they observed no adverse effects at very elevated Mg levels (>2000 ppm). However, others have reported that using Tech-M had negative effects on various livestock, including snails, clams, zoanthids, leathers, anemones, euphyllia, and starfish.
(2) Several people have observed that if the Tech-M treatment results in a large amount of bryopsis dying it can result in the dead bryopsis releasing nutrients into the water, fueling other nuisance algae outbreaks.
Other Issues
(1) Permanence of Treatment -- One concern is whether the Tech-M/magnesium treatment can be used to permanently eradicate bryopsis. Many people have had the experience of seemingly eradicating bryopsis through Tech-M dosing, only to have it recur a few weeks or months later. Others have succeeded in completely eliminating it. Some suggest continuing to dose Tech-m at lower levels (25 ppm) for several months even after the bryopsis appears to be eradicated.
(2) IDing Bryopsis -- A recurring issue in this thread is that people misidentify other types of nuisance hair algae as bryopsis, leading to erroneous conclusions about whether a particular bryopsis treatment works. Also, there are many types of bryopsis and not all may be equally susceptible to treatment.
(3) Signs of Effective Treatment -- People who have had success in dosing Tech-M/magnesium have reported seeing the bryopsis losing color and turning clear, looking "ragged", and eventually falling off the rock or being easy to pull off manually.
(4) Hidden Bryopsis -- People have recommended looking in overflows and other dark places for residual bryopsis even when there's none apparent in the display tank. Apparently bryopsis can survive in these darker areas longer than in well-lit areas.
(5) Chemistry Calculator --
http://reef.diesyst.com/chemcalc/chemcalc.html