How long should cyano take to disappear?

ssick92

New member
Hey everyone,

So I recently got back from summer where my tank was essentially left to do its own thing. I lost my SPS and montiporas due to high nutrients. My nitrate got up to 50 and my phosphate up to .18 on a Hanna meter.

I have done 2 75% and 1 50% water changes and now my levels are undetectable for both. There is also no algae in the tank which points to low nutrients. I completed the last water change last night.

My question is this: I have a little patch of Cyano on one of my rocks, and it doesn't seem to be affected by these water changes. Flow isnt the issue, and I also just changed the lights 2 days ago, so old lights aren't the issue either. How long can this cyano survive in a low nutrient system? I want to avoid doing a lights out period as everything is a little bit stressed from such large water changes and shutting the lights out wouldn't make them any happier.

Also, kind of related, do any of you guys use Brightwell Aquatics Biofuel as a carbon source? I was looking into vodka dosing but my LFS loves this Biofuel stuff so I picked up a bottle and am thinking about trying it out, but want to get some feedback from you guys.
 

lokii_37

New member
Of course your LFS loves the stuff it means you give them money instead of getting the good old cheap vinegar.

can you just suck out the cyano? see if it comes back
 

ssick92

New member
Of course your LFS loves the stuff it means you give them money instead of getting the good old cheap vinegar.

can you just suck out the cyano? see if it comes back

Ya I know most LFS just try to sell as many products as possible but my local LFS is quite different. There have been many times where I was about to buy something from him and he tells me that I can find the same quality stuff at the super market at a fraction of the price. He at least treats me well and helps me save $ whenever possible. However, he really loves this biofuel stuff.

Anyway, I've tried sucking it out but it is in a pretty tough location to get to so it isn't very feasible. Will it go away on its own or will I have to do a lights out period?
 

Vinny Kreyling

Premium Member
Only anecdotal here but when my magnesium went near 1500 the cyano which was BAD decided to go away.
Did the lights out too & it came back just as strong.
 

bertoni

Premium Member
The cyanobacteria might go away on its own. I don't know about the BioFuel product, but it might be fine. Carbon dosing might help reduce the cyanobacteria, but it could take a while. How long has it been since you started the water changes and other work on this problem?

If the feeding rate still is higher than the tank's nutrient export capacity, the cyanobacteria likely will return. Carbon dosing is one approach to increasing export. GFO is easy to run, too, and sometimes helps.
 

ssick92

New member
The cyanobacteria might go away on its own. I don't know about the BioFuel product, but it might be fine. Carbon dosing might help reduce the cyanobacteria, but it could take a while. How long has it been since you started the water changes and other work on this problem?

If the feeding rate still is higher than the tank's nutrient export capacity, the cyanobacteria likely will return. Carbon dosing is one approach to increasing export. GFO is easy to run, too, and sometimes helps.

Its only been 2 days since I got the nitrates all the way down to 0, so I guess it is pretty soon still. All the corals are a lot happier now.
 

bertoni

Premium Member
I'd give the cyanobacteria a week or two to disappear, but I'd get to work right away if it starts to spread.
 

ssick92

New member
Well it doesn't seem to want to go away by itself so I'm going to go 2 days with no lights to see if that gets rid of it. My nutrients are still at 0 and my flow is good so I'm really not sure what is the cause of this cyano. It seems to be in 2 spots only but it does seem to be spreading very slowly.
 

bertoni

Premium Member
Okay, that sounds like a reasonable idea to try now. I probably would run some fresh carbon and GFO once the cyanobacteria starts to die, to help remove nutrients and toxins. A few 15-20% water changes might help, too.
 

tmz

ReefKeeping Mag staff
Premium Member
That patch may be feeding off a nutrient source from the rock under it or some other organic lik coral slime . If there is any detritus near or under it I'd siphon it out or blow it out of the neighboring rock of substrate.
 

ssick92

New member
That patch may be feeding off a nutrient source from the rock under it or some other organic lik coral slime . If there is any detritus near or under it I'd siphon it out or blow it out of the neighboring rock of substrate.

That's exactly what I thought too so I did some investigating but I couldn't come up with any source. If this lights out doesn't work and it comes back as strong then I will probably move some rockwork to really dig down in there and see if I can find something that isn't really noticeable.
 

ssick92

New member
Okay, that sounds like a reasonable idea to try now. I probably would run some fresh carbon and GFO once the cyanobacteria starts to die, to help remove nutrients and toxins. A few 15-20% water changes might help, too.

Ya, my plan is to do the 2 day lights out period and then do a 25% water change. I changed the carbon/GFO a little over a week ago so I'm going to change it when I do the water change as well. Seems like this plan of action should work and I should be all clean, but this hobby always surprises me...
 
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