Cyanobacteria or "Red Slime" algae are probably on every reef keeper's top-ten list of biggest problems in their systems. Stories of hobbyists breaking down entire systems, performing huge water changes or even resorting to the use of dangerous medications, only to have the slime quickly return are not uncommon.
Recently, one of my personal tanks became heavily effected so I thought I would take advantage of the situation and write an article with the details of the infection and how I handled it.
In the beginning, I was sure that I had missed nothing in setting up my dream system. I spent months just doing research and planning prior to actually beginning the system. I had a solid plan and I knew I couldn't go wrong.
A few months later, my system was up and running. I fought the temptation to add any livestock early knowing full well that this would only lead to problems done the road.
I went through a brown diatom bloom that subsided as I knew it would, then a green algae bloom that also quickly subsided. It had been nearly 3 months since first filling my system with water. The time was right and my patience paid off.
Over the next few months, my system came alive with new editions. I added very few fish, hoping to keep the nutrient level very low and instead focused on corals and other invertebrates.
My system sported a properly setup plenum with a 4-inch sand bed as described by Bob Goemans (leading authority on plenum use), a dual refugium system, one with about 30 mangroves, the other with various macro-algae, a great skimmer (A Turbo-floter) and a high-output pump that would more than suffice for water turnover. I even constructed an aerating stand to rest my live rock on to ensure there were no dead spots. Additionally, I purchased an RO/DI unit.
My system was perfect. I had set up a solid defense to prevent any invasion of any algae, diatom or cyanobacteria bloom. But guess what?
It had been 10 months since setting the system up. I noticed a small amount of red slime in several spots as well as a very limited amount of hair algae growth. Surely this was just a small bloom that my system was going through which would pass, right? I decided to let it go hoping it would crash on it's own.
Three months later, I realized that I had a serious problem. Not only had the cyanobacteria and hair algae not gone away, they were beginning to gain a solid foot-hold in the main system as well as the refugium. Still not to the point I have seen in other aquariums, I decided to go to war.
My first action was to begin researching everything I could about my enemy. The SUN TZU (The Art of War) says "know your enemy, know your self". Well, I felt pretty comfortable with myself so I figured I would refresh my memory of every minute detail as far as cyanobacteria were concerned.
I needed to know what my enemy needed to survive. After scouring the internet and books alike, I discovered the following:
Pretty Basic. So if I turned out my lights and stopped feeding all together, the problem would go away! Well that was out of the question, so I figured I would learn more. Here is some information I learned that I thought was important to note:
Hmmmm... number 3 says some forms of cyanobacteria resemble hair algae! Guess what? After a closer look, I discovered this to be my case. I wasn't having a hair algae problem AND a cyanobacteria problem. Just two different cyanobacteria problems at the same time!
#5 says that the species "Oscillatoria" bloom in nutrient rich
environments. Well, duh! I knew that already but my tank could not be
nutrient rich... could it? The thought wondered through my head for a
short time. I couldn't think of any way that heavy nutrients could enter
my system. After all, I only have two very small fish in a 125 gallon
system! So I decided to take a look at everything that enters my system to
try and determine the source.
This is what I came up with:
Perhaps I was on to something. I started to think about my tap water. I knew that in my area, tap water in reef systems could be a problem due to high nutrient content. But I'm using an RO/DI unit! I have been for about a year now, I thought to myself. A year! ...... a year??? Ooops!
I suddenly realized that I never bothered to change my filter cartridges or even find out how often it should be done! Upon researching it, I discovered that the carbon and sediment filters needed changing every few months to help prolong the life of the membrane which did the real work. DOH!!!! I was adding nutrients more and more with each water change and top-off as the filter declined and didn't realize it!
Immediately, I changed my filters and membrane and began kicking myself. I knew I had found the source of my problems but had already allowed the enemy to invade my beautiful paradise! So now that I shut the gates keeping any additional enemies at bay, I needed to figure out how to deal with those who had slipped through.
Common elements from tap-water which lead to algal/diatom/cyanobacteria growth are phosphates, nitrate and silicate. Levels in tap-water for these elements should be as follows:
Remember when I said know your enemy? Well, I had discovered my adversary. It never was the algae, cyanobacteria or diatom growth. They were all just a bi-product of the invasion. Kind' a like burning buildings and lose chickens running everywhere! I had learned how to keep the enemy out, but now I needed to learn how to deal with the enemy within..... my reef aquarium.
Nitrates: A by-product of nitrite and the end product of the nitrogen cycle. Removal from saltwater is simple. Water changes and gaseous exchange. Other than actually replacing the water (which would only be negatively impacted by the remaining cyanobacteria as it died and was removed) my only other option was removal by gaseous exchange. My system had relatively little surface agitation so I added a hang-on back filter to help move the water's surface. Additionally, I purchased a new, more powerful skimmer (a Remora Pro). The Remora Pro worked great and quickly out-performed my Turbo-floter. However, I decided to leave the turbo-floter for now because even though it isn't remove any nutrients through foam production, it is still providing a good amount of gaseous exchange within the skimmer itself. Nitrate Remove was in effect.
Phosphates: Removal of phosphates can be performed in various manner. Aeration similar to that used in removing nitrates helps to remove phosphates so I was on-track there. Additionally, there are various filter medias which effectively remove phosphate. I was already using "Phosguard" so I decided to change it more regularly. I also discovered two things about using kalkwasser (which I had completely stopped using all together some time ago). Firstly, Kalkwasser dosing helps precipitate phosphates out of the water column. Secondly, it helps maintain pH balance, especially if dripped at night. So I began dripping kalkwasser once more but only in the evenings after the lights went out. Phosphate removal was in effect.
Silicates: Diatoms utilize silicates to form their skeletons. I haven't noticed a diatom problem but figure it's best to hit my problem from every area possible so I will include the possibility of having excess silicates as well. According to Julian Sprung (Algae - A Problem Solver Guide) tap water can have silicates in excess of 50ppm. Therefore, even when utilizing an RO unit that is running at peak efficiency, we may still be adding 5ppm silicates directly to our system! Therefore, for some areas a DI unit as well as an RO unit should be used. Thank goodness I am using both. Additionally, I have ordered a Total Dissolved Solids meter which should arrive soon. This will help me determine if my RO/DI unit is working properly as well as when to replace my filters. The meter cost me about $25.00. Definitely a good buy.
Large water changes can lead to a spike in silicates, as can through excessive feedings. Removing silicates from the system can be done as simply as aggressive protein skimming, utilizing grazing herbivores to eat diatoms as they utilize the silicates and just allowing the silicates time to exhaust themselves. Bottom line, shouldn't be a problem as long as my water source is monitored and insured to be as close to silicate-free as possible.
So what else? I have studied the causes of cyanobacteria, what they need to survive and what direct steps to take to remove their food source (ultimately removing them as well), what else can I do?
The final approach that must not be overlooked is looking for allies of my enemy. So back to researching I go! This is what I found and/or already knew:
Keep in mind that these 3 items are only assisters in the growth of unwanted or problematic conditions, not direct causes. Eliminating them will not solve the problem, only help alleviate it.
I am happy to report that after only a few short weeks, my cyanobacteria is almost gone. The Oscillatoria variety seems to be completely eradicated, and the Lyngbya variety (which I had originally thought to be hair algae) is well on it's way.
After reading this article, I hope you as well are on your way to beating this problem. Here are some additional pointers to keep in mind when fighting a bloom or trying to avoid one: