Brown Slime / "Snot" Algae
I'm posting this given the importance of the information in hopes that should someone else have this trouble it will show up on an Internet search. This is an individual who e-mailed Seachem with regard to his experiences with this algae:
comments: Dear Seachem,
I thought you might be interested in hearing a story about my experience with a dreaded and tenacious form of algae/cyanobacteria commonly known as Brown Slime or "Snot" algae, and how it finally wound up being cured by one of your products. It seems that most people (and most pet shops) have never had the misfortune of encountering this stuff, which starts out as a brown dusting on the substrate, rocks, glass, etc, growing like crazy literally overnight, and developing a lot of air bubbles within it. It grows into long, filamentous form, filled with air bubbles, but lacks true hairlike structure or definition. In a matter of a few days to a week it can completely overrun a reef tank. It came out of nowhere in my tank, likely brought in on a piece of live rock, and I fought and fought to try to erradicate it (or at least control it) for the better part of a year. All the while, Phosphates and Nitrates read zero, and I tried to keep the tank very clean, limiting feeding, etc. But I still literally had to scrub all of the glass, rocks, etc. every single day, sometimes more than once, just to keep up with this horrid stuff. I have an external overflow on my tank, and the air bubbles from the brown slime algae would find their way up into the siphon tubes, causing the outflow to the sump to slow down, (and hence the water in the tank to rise). I had to siphon the air out of the tubes at least every 2 or 3 days to avert a disaster, and one morning I awoke to find the tank overflowing onto the floor because of this problem. The cyano finally choked out and killed all of my corals, and turned my 75 gallon reef tank into one big swamp.
Asking advice from various pet stores specializing in reef life (as far away as 180 miles), I tried tearing the entire tank down, scrubbing the rocks, rinsing the aragonite, and cleaning all of the equipment. A few days after I set it all back up again, the slime returned. I added a small army of various types of snails and hermit crabs, a stafish, etc. Even they couldn't keep up with the goo. I next was advised to use Erythromycin. This seemed to slow it down, but after the 4-day treatment, it returned with a vengeance. The pet store next advised to try doubling the Erythromycin dose, and to use it for 5 days. It still didn't phase the stuff. A really large reef store 180 miles away in Washington, DC told me that I should just bleach everything and start over! Several sources, both pet stores and online experts said that what I needed was a refugium with macroalgae, to outcompete the cyano/algae for the nutrients in the water, to control the source of the problem. I built one, stocked it with Chaetomorpha, and put it on RDP lighting. This did bring the brown slime more or less under control, but still did not completely irradicate it. It still would grow in places that the snails could not get to, (such as inside the aforementioned overflow boxes). Somewhere during all of this mess I also had a heater malfunction on me, and woke up one morning to find the water in my tank at 90 degrees F, which stressed my fish and caused an outbreak of cryptocaryon. I did Freshwater dips on all of the fish, treated them for 2 weeks (in a quarantine tank) with copper, and did a 6 week fallow period on the main tank, with no fish in it. During that time, sans fish, the brown slime algae remained mostly under control, but was still there. When I returned the fish to the tank following the 6 week fallow period, I thought that maybe I'd go ahead and run a canister filter with Seachem's Cuprisorb in it, just to be on the safe side - to be sure that the fish didn't bring any trace of copper back into the system with them. Within a week, two very notable things happened. My chaetomorpha macroalgae suddenly started to die off, and the tenacious-as-hell brown slime algae just up and vanished, gone without a trace. It took me almost a week of desperately trying this and that to save my Chaetomorpha, (thinking that its dying off had something to do with the fish coming back into the system), before it dawned on me that all of this had happened after I'd started to run the canister filter with the Cuprisorb in it. (I'd forgotten to order a micron bag to put the cuprisorb in, and had taken an old white handkerchief and sewn it into a small "sock", which I then put the Cuprisorb into)! I did some searching on the internet, and found on Seachem's FAQ page that the Cuprisorb, in addition to removing copper and heavy metals from the water, will also remove IRON and manganese! I bought a bottle of iron supplement, added a few small doses, and my Chaetomorpha sprang back to life. I'd just recently talked to the owner of a local pet store who said he had the same brown slime algae problem in his own reef tank at home, and hadn't been able to find a solution to it. After making my discovery, I ran down to his shop and told him I'd found a simple cure to the problem: Seachem Cuprisorb, in an old handkerchief in a canister filter for a week or so! The brown slime/snot algae is obviously dependent on iron for its growth, and taking the iron out of the water kills it quickly! Afterward, it's a simple matter to add a little iron back into the tank, to support any macroalgae that might be in the refugium. I have since also phoned the "experts" in the Richmond, VA store, (who'd first advised using the Erythromycin, and then later suggested the refugium), and broke the news to them. They seemed to be extremely interested.
So the story definitely has a happy ending, and I hope to share this discovery with other reefkeepers with brown slime/snot algae problems in the future. Thank you Seachem! Your Cuprisorb has literally saved a reef!