Help! Cyno!


New member
Ive got a bit of a cyno problem in my 60 gal. Id like to know:

(1) What're the typical causes of Cyno?
(2) How do I get rid of it?
(3) You ever have cyno/How did u get rid of it?

happy reefin'

Lev F.

New member
The Three Most Common Causes Causes of Cyanobacteria : By Lev

1. Nitrate or Phosphate
2. Not enough flow towards the affected area
3. Overfeeding, Nutrients

Combatting Cyanobacteria

Scenario 1: Nitrate is too high
Increase the amount of Water Changes

Scenario 2: Not enough flow
Increase amount of flow towards affected area.

Scenario 3: Too much nutrients
Decrease feeding, feed sparingly.

Good Luck! :D

Blown 346

New member
The typical causes of cyano are...
1. Low to no flow areas
2. High Phosphates
3. Excess nutrients/organics
4. Not having a skimmer
5. not keeping up on maintenance.
6. ovefeeding

To get rid of it you will nedd to find what is causing it, but that can be difficult since if you go try and est for it, your test might read everything is fine. But that will happen since the algae is using up the organics or phosphates faster than your test can read.
Check how often and how much you feed, After you feed, if there is still food in the tank after 3 minutes you over feed. Watch how much you dose plankton etc.

The only time I had it was when my tank was new and was going thru the algae cycles. I just siphoned what I could out and kept up maintenance, and made sure i had good flow throughout the tank.


Premium Member
Get a copy of Julian Sprung's "Algae: A Problem Solver Guide" While you are waiting for it in the post, here is what I personally do to get rid of this pest:

1) Use only 0 TDS RO/DI water for top-off and making up new seawater. I have a Typhoon III from which I and many others here consider to be the best unit for the money.
why: tap water has all sorts of minerals in it which, even at the smallest concentrations, provide food for the algae.

2) Start testing your alkalinity weekly and dose a good alkalinity buffer or Kalkwasser if it is low.
why: alkalinity retards the growth of many species of pest algae.

3) Get a high quality protein skimmer if you don't have one already and run it 24/7. This is one piece of equipment where you should be prepared to make an investment. There is an excellent skimmer thread in the "All Things Salty" forum on skimmers and how to tune them up.
why: dissolved organic compounds (DOCs) either directly, or by breaking down into simpler compounds such as nitrates, provide food for algae.

4) Consider adding a live refugium to your system. If you have a sump already, chances are you can convert it to a refugium.
why: the macroalgae growing in a live refugium compete with the algae in the main tank for nutrients (DOCs, nitrates, etc) making it harder for them to proliferate.

5) Free up any mats on your live rock with a toothbrush and suck them out with a siphon. Free up any colonies on the tank walls with an (acrylic safe) cleaning pad. Again, suck out whatever you can see with a siphon.
why: As you begin to remove the food sources for the algae from your tank, some of the algae will die off and decay, adding more nutrients to your tank water and prolonging the growth of the remaining algae.

6) Start doing smaller and more frequent water changes. In my small tanks, this means 10% twice a week. Small for me is anything less than 50 gallons, btw. Use a siphon with a vacuum attachment and try to get all of the brown gook out of the top 1" or so of your substrate.
why: Nutrients build up in your tank over time, both in the water and in the substrate. The longer these nutrients build up, the stronger the growth of the algae you are trying to remove.

7) Start feeding smaller amounts of food more frequently. I use a chef knife to shave paper thin slices of frozen Formula 1 and 2 gel blocks, which I feed 3 times a day.
why: the food we add to our tanks is wonderful algae food, especially as the uneaten particles fall to the bottom of the tank and decay. Adding less food more frequently ensures that the fish comsume as much of the food as possible, leaving less food for the algae.

8) Eliminate any sources of phosphate from your tank. Check your fresh salt mix and your activated carbon with your PO4 test kit. Stop feeding mysis or at least thoroughly wash them in RO water before you put them in the tank. Use phosban to get rid of whatever phosphate is in your tank already.
why: phosphate is a well-known nutrient for many types of algae.

9) If you are using power compacts or VHOs, change your bulbs and add some cooling fans so that your bulbs will last longer. Cool bulbs will last 8 months, overheating bulbs will last only 3-4 months.
why: over time, the wavelength distribution of fluorescent lights changes from being centered on the blue wavelengths to being centered on the red wavelengths. The blue wavelengths are more favorable to corals, while the red wavelengths are more favorable to algae. Overheating accelerates this aging process.


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