Still dealing with cyano

[Sophie"s mom]

I appreciate your input, sir! I agree with what you say. I found that the coral snow + bacteria has really slowed down the Cyano and allowed me to get ahead of it. I was absolutely a cause of the problem, having too little flow over the sand bed in particular. I have since added a tiny, cheap flow pump just to fly low over the sand surface. I am certain the battle back and forth would be ongoing had I not fixed that. But I am grateful to the coral snow + bacteria for helping in the meantime. Anyone looking for a silver bullet should look elsewhere.

100% agree. My problem as well is low flow over the sandbed. I too will be fixing that with a very small powerhead I have that should fit in my back corner.

 

[noworlater]

I'm a new reefer 6-7 months had my fair share of cyano! What i did that helped it lowered my lighg wayyy down mostly blues for about 2 weeks 4-5hrs a day. After the 2 weeks everything nice and clean! Now my tank never been cleaner! And i do 2-6-2 lighting peak 6hrs 70% blue, 15% white. My tank is thriving!!!! Please trust me n take my advice! And you need a good clean up crew! Get alot of snails!

I have lots of snails, but may get more. Yeah, I am thinking about changing my lighting schedule. They currently are more scheduled around my being there to feed the fish. So they come on before I go to work, and are on until I get home from work to feed again.

If i were you stop adding stuff in there. You gotta be patient! Weekly water change, siphon sandbed, lower lights, kick back on feeding too much. You should be good in 2 weeks!!! Add bioculture it helps!

 

[Jackal799]

Just recently beat cyano without chemiclean. Nutrients were dang near perfect phosphates of .08 and nitrates of 10. Still got it. When I did was immediately start manual removal on some patches I would inject hydrogen peroxide and watch it die instantly. Anyway, following manual removal I added 1 pound of aquabiomics gulf sand. I smothered that cyano with it. I then cut my lights for 48 hours and it’s been two week, no cyano has come back. I do believe you can outcompete cyano pretty easily but you have to edge the war in your favor by minimizing fuel (light). I have also been successful by mixing coral snow with microbacter 7 and literally smothering it using a syringe full of the snow. I just don’t like using a ton of microbacter 7 so I went the aquabiomics route.

 

[Euphylliaphyle]

That sounds like a great, albeit expensive alternative, especially useful if you need to replenish some sand in your tank.
What is it about Microbacter7 that you do not like, and what do you consider "a ton" of it? I use 7 drops in my 36-gallon once every 10 days with water change and coral snow treatment.

 

[Paul B]

My reef is very old and it comes and goes. I don't pay any attention to it as it is normal and natural.

 

[Euphylliaphyle]

My reef is very old and it comes and goes. I don't pay any attention to it as it is normal and natural.

I thought it was actually quite nice, but my wife likes things more tidy.

 

[Sophie"s mom]

My reef is very old and it comes and goes. I don't pay any attention to it as it is normal and natural.

aww, adorable little fish! Thank you for sharing!

 

[Paul B]

I thought it was actually quite nice, but my wife likes things more tidy.

I've been married for over 50 years, and my wife doesn't even know I have a fish tank. Some day I am going to tell her.

 

[docaquarium]

The updated instructions for use, unfortunately, are confounded in the post with the original version, but if you read through the entire post you can see where he recommends running circulation pumps only (no skimmer, no other filtration) for the first hour after dosing. This reportedly allows time for the bacteria to establish on solid surfaces within the tank before turning on filtration, including skimmer, to clarify the water.
Anecdotally, I followed these directions for two water changes (including turkey-basting rocks, scraping glass, and removing visible cyano from the sand bed) and have seen a significant reduction in cyano already, and it is clearly not reestablishing itself on the sandbed nearly as quickly as it had been before treatment, when I was already using the same water change/tank cleaning routine otherwise.

Understood, although directions for most bacteria's recommend a much longer time period. Some products recommend 4-8 hours for bacteria to settle if not longer. The calcium carbonate powder (white snow) along will help reduce the cyano as it binds to it which later gets skimmed out. This is only my personal thought as there are other great ways to approach this. I would skip adding beneficial bacteria to your mix. Instead add it later after the whole reaction process has removed a lot of the bad bacteria along with some good. This will help reestablish the bacterias you want. What would also be good is adding bacteriocins formulated to aid the good bacteria that fight against the bad.

Dosing a calcium carbonate “white snow” solution in a reef tank isn’t really a biological reaction first—it’s a chemical precipitation event that then triggers some secondary biological effects.
Here’s what’s actually happening:

1. Immediate chemical reaction (the main event)​

When you add a “white snow” solution (typically a fine slurry of CaCO₃ or something that rapidly forms it), you’re essentially forcing this equilibrium:
- Dissolved calcium (Ca²⁺) + carbonate (CO₃²⁻) → solid calcium carbonate (CaCO₃). This forms tiny suspended particles—your “snow.”
At the same time:
Alkalinity drops (carbonate is consumed)
Calcium may drop slightly (depending on how it was dosed)
pH can spike briefly if carbonate concentration increases before precipitation

2. Flocculation & adsorption (why people dose it)​

Those fine CaCO₃ particles act like a magnet for impurities:
Bind phosphate (PO₄³⁻) → reduces measurable PO₄
Adsorb dissolved organics
Trap bacteria and detritus
This is why the water often clears after—it’s similar in concept to a flocculant.

3. Biological response (secondary effects)​

Now the “bio reaction” part:

a) Bacterial impact​

Some free-floating bacteria get physically removed as they bind to particles and get skimmed out
Can slightly reduce bacterial load in the water column
Does not directly kill bacteria (unless pH spikes hard)

b) Coral & microfauna response​

Corals may produce mucus if particles irritate tissue
Fine particles can temporarily coat polyps, reducing light and gas exchange
Usually harmless if done lightly, but heavy dosing can stress SPS

c) Nutrient dynamics​

By removing phosphate and organics, you can:
Improve water clarity
Potentially limit bacterial growth (less DOC)
Shift nutrient balance (watch for ULNS swings)

 

[Sophie"s mom]

My mature tank got cyano in one corner, I tried to wait it out a few months but it stayed but didn't get better or worse. One day I siphoned the sand, I stuck the siphon in the sand, suck it up and pinch the hose for the sand to fall then siphon the black cloud, I did this twice and the cyano went away. I don't know how or why it worked but it did.

I know you said you didn't want to lose sand, but just putting the idea out there. My sand is 3"-4" deep so I don't mind losing a little

A question, I was siphoning out some cyano this morning and accidentally got a small piece of one of my dragon soul torches! Will this cause problems for that torch?

 

[Mr. Mojo Rising]

A question, I was siphoning out some cyano this morning and accidentally got a small piece of one of my dragon soul torches! Will this cause problems for that torch?

I hope it will be ok, but I've never owned a torch so I can't help with this one sorry and good luck

 

[Sophie"s mom]

I hope it will be ok, but I've never owned a torch so I can't help with this one sorry and good luck

Thank you

 

[Euphylliaphyle]

I have no idea, but a hunch that nature has equipped them to deal with such things. Not siphoning, per se, but having tentacles ripped off generally. Hopefully it will heal just fine and get about living it's best life. In fear of siphons perhaps, but just groovy otherwise.

 

[Sophie"s mom]

I have no idea, but a hunch that nature has equipped them to deal with such things. Not siphoning, per se, but having tentacles ripped off generally. Hopefully it will heal just fine and get about living it's best life. In fear of siphons perhaps, but just groovy otherwise.

lol yeah that’s what I am thinking and hoping! So far it is still extending and looks fine! Thank you for the reply

 

[Anonymous'Reefer90]

No tuve éxito con las bacterias ni con el carbonato de calcio en polvo, pero el antibiótico tilosina de Chemiclean resultó ser muy eficaz contra las cianobacterias. Sin embargo, es posible que haya contribuido o no a un problema con la anémona magnifica.

Es ciertoIt's true, I had problems with green cyanobacteria for more than a year, my parameters were stable and I had a good flow or they went away but decreased, I ended up opting for chemiclean and so far they haven't returned.

 

[Sophie"s mom]

Hey everyone! So another thing I am going to do to help reduce this cyano is 2 separate things with my lighting. 1) I am going to reduce the white, and I believe (correct me please if I am wrong here) this must done in increments, not all at once. and 2) I want to reduce the hours that the lights are on. So my question here is should this also be done incrementally, or can I just go in and adjust the time the lights are on and be done with that part? Thank you in advance for any and all answers here.

 

[vlangel]

Hey everyone! So another thing I am going to do to help reduce this cyano is 2 separate things with my lighting. 1) I am going to reduce the white, and I believe (correct me please if I am wrong here) this must done in increments, not all at once. and 2) I want to reduce the hours that the lights are on. So my question here is should this also be done incrementally, or can I just go in and adjust the time the lights are on and be done with that part? Thank you in advance for any and all answers here.

I did the same thing although I did not change the duration. However, I did change the intensity of the white and red channels in small increments. I decreased each hour by either 5 or 10% a week. That seemed to be ok with the coral as I have seen no negative effects.

 

[Sophie"s mom]

I need to change the duration by quite a bit. I leave at 7 a.m. so at the point the lights have been on for 30 minutes so I can feed the fish before I leave. I don't get home until about 6 p.m. so the lights don't start dimming down until about 7 p.m. that way I can feed the fish again when I get home. So that is about 13 hours of light in all. That is a heck of a lot! so what I really want to do is have them start to come on at 7 a.m., and start dimming down at 6 p.m. that will cut about 2 hours of light out, and still (usually at least) give me time to feed twice a day. can I make this change in one shot, or should I do so slowly? I know cutting back on the amount of white should be done slowly.

 

[vlangel]

I need to change the duration by quite a bit. I leave at 7 a.m. so at the point the lights have been on for 30 minutes so I can feed the fish before I leave. I don't get home until about 6 p.m. so the lights don't start dimming down until about 7 p.m. that way I can feed the fish again when I get home. So that is about 13 hours of light in all. That is a heck of a lot! so what I really want to do is have them start to come on at 7 a.m., and start dimming down at 6 p.m. that will cut about 2 hours of light out, and still (usually at least) give me time to feed twice a day. can I make this change in one shot, or should I do so slowly? I know cutting back on the amount of white should be done slowly.

I think I would still not do it in one shot. Maybe cut it in half and do it with a week between the 1st reduction and the 2nd. Doing it in one shot might not hurt but I would hate to be wrong about that.

 

[Sophie"s mom]

I think I would still not do it in one shot. Maybe cut it in half and do it with a week between the 1st reduction and the 2nd. Doing it in one shot might not hurt but I would hate to be wrong about that.

Yeah better safe than sorry for sure! Thank you for the input here. I would think? it should be fine since I am not changing the intensity ( at least not yet) . But, like you, I would hate to be wrong.