Sadly, my experience says that raising your Mg level may slow it, but it will not rid the problem from your tank. Even worse, once you have bryopsis, it will never be truly eradicated but rather controlled.
Kent Tech M
will rid your tank of bryopsis if you use it correctly. Not control it, but eradicate it. I did in my 300 gallon DD tank two years ago and it has not come back. Here are my dosing insructions that worked for me.
And BTW, Red Sea magnesium test kits read higher than Salifert or Elos at any concentration. I would use Elos or Salifert before Red Sea any day.
Tech M dosing instructions:
Acroporaddict's Tech M Dosing Instructions
This is the method that worked for me. Of course, you follow these at your own risk, etc.
1. Get enough Tech M to do the job. Do not use mag sulfate or mag chloride to raise the mag level so you don't have to use as much Tech M. If you do this you are not adding the trace element or whatever is in the Tech M that actually kills the Bryopsis. Start from whatever your mag level is and raise it only using Tech M.
2. Get a quality test kit, like an Elos or a Salifert. Test every day when you are raising mag levels and when you are maintaining mag levels. Salifert test kits only read to 1500 ppm, so when you know your mag levels are over 1500, you add 1 ml of the #3 reagent and then draw up another 1 ml per the instructions. When you get the color change, reference the chart for the ppm, then add 1500 to this for the total ppm.
3. If you use them, I would eliminate the use of any Poly Filters or the like during the time you are raising the Mag level to 1800 with Tech M until the time your mag level drops to 1350 as described in step 6. Poly filters can remove metals, and since no one knows, you might remove the trace element that is actually killing the bryopsis if you use poly filters. Carbon is fine.
4. Raise your magnesium with Tech M by 100 ppm/day until you reach 1800. Test every day and maintain this level in your reef for two weeks straight. Do not do any water changes during this time. If you do water changes, then make sure you add enough Tech M to the tank to maintain the mag at 1800. The idea is to get enough exposure time at that level so whatever trace element is killing the Bryopsis has enough time to work.
The 1800 mag level is an indirect indicator of the concentration whatever trace element in the Tech M is killing the Bryopsis. Length of exposure at the right concentration seems to be the key to eliminating vs just suppressing the Bryopsis.
5. If you have a lot of Bryopsis in your tank, manually remove as much as possible when it starts to weaken and die. This will eliminate/minimize an ammonia spike that can result from the decaying Bryopsis.
6. After you have maintained a mag level of 1800 for two weeks, start doing your normal water changes. Do not do them more often that usual. You will have elevated magnesium levels for a period afterwards, several weeks probably. This is not an issue. Let the level come back to the normal 1350 or so thru regular water changes and use by the corals.
7. Possible effects on animals and corals. I had some turbo snails die in the time my mag levels were elevated. I also had some montiporas lightly bleach on me, but they recovered quickly. I lost no SPS, LPS or soft corals as a result of using Tech M in the manner I have just described.
Again, please keep in mind that the above regimen worked for me. Know that Kent Tech M is not manufactured or intended by Kent Marine as an algaecide against Bryopsis. The effect of Tech M on Bryopsis is a side effect of this product when it is used at a much higher than normal concentration, so all treatment regimens for Bryopsis by me or anyone else are based on anecdotal experience only.
