As far as algae problems go in saltwater aquariums (primarily reef aquariums), none is as nightmarish as bryopsis. It just doesn’t go away with normal efforts the work on fighting most other algae outbreaks. But here I am going to give you a solution that actually works, and believe it or not, it works pretty fast too.
There are many types of algae outbreaks, such as hair algae, cyanobacteria (i.e. red/green slime algae), diatoms, bubble algae, etc.. But when it comes solving the algae outbreak, bryopsis is in a class all by itself. In most cases, you can manage your way out of the problem, by reducing nitrates and phosphates, elevating pH (8.4-8.5), increasing water movement, adding a diverse army of grazers (tangs, emerald crabs, hermit crabs, sea hares, urchins, snails, etc.), and removing detritus from the system, as well as other steps.
But bryopsis algae does just fine even after you add an army of inverts to graze, because few will eat it. Also, it can still thrive even when phosphates and nitrates are at zero (or undetectable). And even if you have a refugium attached to your saltwater aquarium or reef aquarium, the bryopsis algae just keeps on keeping on. It does not need much in the way of nutrients to sustain itself, unlike cyanobacteria (i.e. red/green slime algae), which can easily be reduced with phosphate removing media, increased water movement and detritus removal (not to mention a product called Chemi-Clean, which nukes it instantly, but does not deal with the cause).
And manual removal of bryopsis is an exercise in futility. It will actually help it reproduce via asexual fragmentation.
So by now your wondering “alright already – give me this elusive solution”. OK here it is.
The solution to nuking, wiping out, a bryopsis outbreak (no matter how massive the outbreak), is to raise the magnesium levels to 1600ppm (normal levels ~1300ppm) and keep it there for 3 months. Do not raise it faster than by 100ppm per day. Once you have your magnesium levels at 1600ppm, there may be a slight increase in algal growth (at first), and then the bryopsis algae will shut down and begin to fade and die off, whereby your grazers (snails, hermits, emerald crabs, tangs, etc.) will eat it. Once successful, lower Magnesium levels to 1300ppm and keep it there long term.
Once the Bryopsis reaches its threshold for binding Magnesium, the Magnesium will then function as an enzyme inhibitor and cause the Bryopsis to shutdown and die off.
To raise your magnesium levels, there are many different products you can use, such as:
- Kent Tech M
- Magnesium chloride
- SeaChem Reef Advantage
And once you have the problem licked, it is vitally important to focus on prevention. This means maximizing high water circulation in your aquarium, continual removal of detritus, efficient protein skimming, keep pH at 8.4, use several forms of removing phosphates and preventing their addition to your saltwater aquarium:
- use phosphate removing media such as Rowaphos or Puraphos;
- employ use of chaetomorpha and gracilaria algae in a refugium;
- use calcium hydroxide (a.k.a. kalkwasser) to precipitate out phosphate so that the protein skimmer can remove it; it also elevates the pH and contributes to calcium and alkalinity;
- filter tap water with RO/DI (reverse osmosis with deionization post filters) as it removes phosphates from tapwater;
- thaw out and rinse all frozen foods prior to feeding them to your saltwater aquarium, as just looking at the thaw water will show you there is a lot of unwanted nutrients that would otherwise end up in your tank and contribute to algae problems;
- service your protein skimmer at least once a week and keep it functioning at peak efficiency
Here’s to your success in staying ahead of the game and to preventing such nasty problems as a bryopsis algae outbreak. Remember to keep an eye out for bryopsis attached to new coral additions or live rock. Now that you have the solution, we’d love to hear your feedback, by commenting on our blog, which can be found in the author resource box below this article.