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Why do I still have cyano?


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I thought that if my nitrates were at 0 there would be nothing left for the cyano to feed off? My tank has been running for 2 months. Nitrates were high but have been at 0 for a week now. Can someone enlighten me?

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Cyano is also caused by an excess in phosphates and nutrients in general. Also, the length of your light period (how long you keep your lights on) will affect the growth of cyano. Cyano is tough to get rid of, even if your nitrates are at 0, it will take time to get rid of. There are a few steps to combat the ugly red stuff.


feed less

shorter light period

direct water flow into affected area

make sure SW is made with RO/DI (RO, distilled is usually okay)

siphon or pick off cyano

change sponge, floss, carbon, periodically if used

water changes and the use of a skimmer are key IMO


With that, you'll usually be able to get rid of it...it worked for me.

Good luck :)

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time, that helps too, your tank is young, you will go through many blooms, cyano blooms, diatom blooms, hair algae, just stay on the right path, do your water changes, dont over feed, make sure you change your bulbs when need be, and dont overstock and you will be home free....two years from now....just be patient, if you are doing all of the above it will go away on its own. You arent using tap water for top off are you?

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No, not using tap water for top off, I've got RO water. Thanks for your helps guys. I'm doing all of what you say, so I guess I just wait it out.

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Feed less and reduce light duration is all good advice, but when keeping a reef tank it is rarely done by anyone. When you start adding more livestock and feed more it's hard not to get algae, one you want to make sure your corals and fish are feed, and two, your biocube doesn't come with the best biofilter. So there are things you need to do to upgrade it to handle more livestock. You'll need something to compete for the excess nutrients to minimize nusiance algae, so my first choice would be to add some mangroves and macros (calupra and chaeto), both cheap and easy to grow, and address the longterm reduction of managing nusiance algae. The mangroves and macros will also increase the bio diversity in your tank, making it a much healthier environment for your corals and fish. Do a water change ever two weeks until you see a reduction in nusiance algae, once a month when you have it under control. After a month or so, if your still having cyano problems, start scrubbing your rock and removing as much of it as you can, clean the rocks outside of your tank in waterchange water, not inside, don't blow it around in your tank because that just spreads it around and it will just grow back. These steps are just good tank maintenence, and should be done on a regular basis. Cleaning the glass, removing detritus from the bottom of the tank, this will all help reduce algae growth and this is daily stuff that you will just have to get used to if your seriuos about keeping a reef tank.


If after a few months this does not help, you will need to upgrade the filtering system. For instance if you have more than 5 corals and 2 fish and your feeding them frozen brine, than you have reached the limit of a Nano Cubes stock filtration, you will need to get a simple JBJ skimmer plate, it's just a plastic piece that goes over the water intake that skimms the surface water clean. You also might want to do the back compartment refugium mod, add a nano skimmer, lots of things you could do, but try the earlier mentioned first.


After you've got bio filtration under control and your tank is full of stuff, then it's time to upgrade those lights :o

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