1. Identifying the problem

Cyanbacteria (cyano) is often confused with Algae, it comes in different colours and forms but heres the easiest way to identify.

If its brown, stringy and has bubbles its NOT cyano, its Dino which is a whole different topic

Cyano is very common as a purple / red colour, it also comes in less common blue and green flavours. Its slimly looking to the eye and is very easily removable with a brush or better still a siphon tube. If it doesnt pull off easily then its NOT cyanobacteria

2. When does it occur

Well in our experience cyanobacteria usually but not always appears when you have a new tank, we find its very common in marine aquariums less than 3 months old, this is due to imbalances in nutrients, phosphates and nitrates because the tank is new and still finding its rythm this is a very common time to see the signs of cyanobacteria.

We also even in our very well established aquariums often see cyano at least once a year, it mainly appears in the tanks nearest our stores main entrance. It always occurs during the same change of the season and we firmly beleive that pollen can cause cyano outbreaks. The pollen and sugar stealers (floating seeds) find their way into our tank and presumably result in again an imbalance of levels within our marine aquarium.

3. How to rid yourself of this pesky unsightly coral killer. 

Ask on facebook and you will be met with a rapid flurry of reasons and ideas of how to rid yourself of cyanobacteria. 

1. Reducing lighting: We find this has no effect because cyano is not light dependant, overnight when your lights are off the cyano will appear to have vanished but within a couple of hours of the lighting being on it will return.

2. Flow. Changing your flow can have an effect on cyanobacteria, it will help to clear affected areas but you may find it just appears in other areas instead. 

3. Nutrient control. Controlling your phosphate and nitrate is important in a reef tank, but this in our experience doesnt always to be the solution to cyano bacteria. In many cases if your phosphates and nitrates are out of sync this could of course address the problem so if your levels are wrong then this is a great place to start to recitify your issues but we have good balanced levels in our display and the pollen induced cyano is not affected by levels.

4. Chemical treatment. Often a last resort by many people who are against the use of chemicals in their tanks (ironic considering a glass box of fish in your living room isnt exactly natural) but i can understand where they are coming from but treatments are fast acting and they solve the issue which leads to less people getting disheartened with their tanks. We reccomend the use of Chemiclean (not available in the UK anymore) and we also use Bluelife Cyano RX. Treatment should be as per the box instrucitons but generally we remove all carbon additives, turn off UV steralisers and switch off any Ozone units. We also remove the cup from our skimmers but leave the skimmers on for oxygenation. The skimmer is going to go into a mad bubble frenzy for a while filling your cup but the treatment also uses oxygen from the water so this is our preferred method of dealing with the over bubbling and the oxygen. After 48 hours a large water change should be performed and carbon can be used to remove the treatment, you may find it takes a week or more for the skimmer to settle back to previous levels.


Left unchecked Cyanobacteria can kill coral by smothering them, so please get on top of this issue as soon as it appears hopefully the details above can help you acheive a healthy cyano free marine aquarium.