Another Cyano Post

[Emerson]

I have a new tank build, up since March (6 mos): 75 gal DT, 20 gal sump w/ Kessil H80 over good growing chaeto in refugium, Vertex 130 skimmer, BRS GFO/Carbon reactor, 2 x Tunze powerheads, RODI water w/ TDS<1 ppm, 2 x Kessil A360 @ 12.5 hrs a day (~4 hrs @ 100% intensity), and Iwaki external return pump at ~ 10x /hr turnover.

T=77-79 deg, ph=8.0-8.3, ORP=440-490, SG=1.025, Alk=8.0-9.0, Ca=440 ppm, Mg~1350 ppm, NO3~0-2 ppm, PO4=0 ppm.

7 x small fish, 8 x trochus snails, 1 fighting conch, 4 x nassarius snails, ~10 hermit crabs, 3 x emerald crabs, 2 x peppermint shrimp, handful of mixed corals.

A month ago I started increasing the light intensity from peak of 60% intensity to 100% intensity and got a cyanobacteria bloom I can't get rid of. I keep beating it back, dislodging with a baster and removing as much as possible during 25% water change. It keeps coming back. I'm trying to avoid using a chemical slime remover, but worried if I don't keep it in check or defeat it it will take over.

What I can't figure out is: what is driving the cyano? NO3 and PO4 are at or near 0, photo period is normal, I don't over feed, and other water parameters are good.
Any ideas/thoughts before I take the chemical option? Thanks in advance for your insights.

 

[Brew12]

I have a new tank build, up since March (6 mos): 75 gal DT, 20 gal sump w/ Kessil H80 over good growing chaeto in refugium, Vertex 130 skimmer, BRS GFO/Carbon reactor, 2 x Tunze powerheads, RODI water w/ TDS<1 ppm, 2 x Kessil A360 @ 12.5 hrs a day (~4 hrs @ 100% intensity), and Iwaki external return pump at ~ 10x /hr turnover.

T=77-79 deg, ph=8.0-8.3, ORP=440-490, SG=1.025, Alk=8.0-9.0, Ca=440 ppm, Mg~1350 ppm, NO3~0-2 ppm, PO4=0 ppm.

7 x small fish, 8 x trochus snails, 1 fighting conch, 4 x nassarius snails, ~10 hermit crabs, 3 x emerald crabs, 2 x peppermint shrimp, handful of mixed corals.

A month ago I started increasing the light intensity from peak of 60% intensity to 100% intensity and got a cyanobacteria bloom I can't get rid of. I keep beating it back, dislodging with a baster and removing as much as possible during 25% water change. It keeps coming back. I'm trying to avoid using a chemical slime remover, but worried if I don't keep it in check or defeat it it will take over.

What I can't figure out is: what is driving the cyano? NO3 and PO4 are at or near 0, photo period is normal, I don't over feed, and other water parameters are good.
Any ideas/thoughts before I take the chemical option? Thanks in advance for your insights.

My experience has been that Cyano likes a low NO3 environment. If I see it I can normally clear it right up by letting my NO3 rise to the 15ppm to 20ppm range.

 

[Emerson]

My experience has been that Cyano likes a low NO3 environment. If I see it I can normally clear it right up by letting my NO3 rise to the 15ppm to 20ppm range.

Thanks for the reply.

...Interesting. I would think nitrates in that range might be detrimental to the coral growth? How do you get your NO3 to rise? Once there, and the cyano is gone, do you find you can bring the level back down without a recurrence?

 

[Brew12]

Thanks for the reply.

...Interesting. I would think nitrates in that range might be detrimental to the coral growth? How do you get your NO3 to rise? Once there, and the cyano is gone, do you find you can bring the level back down without a recurrence?

Lots of ways to get there. Skim less, feed more, dosing. Lots of options. As for the impact of NO3, I recommend reading this. I feel most people are surprised when they see that some of these "experts" maintain between 5ppm and 20ppm NO3 in their systems.
https://www.reef2reef.com/ams/tank-parameters-of-some-masters.263/

 

[Stevesreef225]

Can ultra low p04 contribute to cyano? I’m dealing with a similar problem in my newly set up 100 gal. Using ultra high coppacity gfo, I went by from 40ppm to 0. The cyano showed up when the p04 got to the very low levels. I experienced the same thing in my 50 gal.

 

[Benqb007]

I battled for a long time, then went 72 hrs straight no lights and did a huge water change; 75% of the Cyano was gone. After another month, I did the same thing and knocked out the rest.

 

[Brew12]

Can ultra low p04 contribute to cyano? I’m dealing with a similar problem in my newly set up 100 gal. Using ultra high coppacity gfo, I went by from 40ppm to 0. The cyano showed up when the p04 got to the very low levels. I experienced the same thing in my 50 gal.

I'm more used to seeing dino's from too much GFO but some strains of cyano are possible, too.

 

[Emerson]

UPDATE:
I finally tried UltraLife Red Slime Remover; seemed to knock it down, but came back. Tried a second dose with same results.
Based on YouTube video on this forum by reefwiser and twillard (thanks again guys!), I finally defeating cyano by dosing 1ml/ 10 gal tank water of 3% H2O2 (8 ml in my case), 1 x per day, for a week, then going to 2 x per day for another three weeks. I would blast the dead/dying cyano with a turkey baster and catch as much as I could with a net or sock. Also ran my skimmer a little wet to get rid of any organic die-off.
I had absolutely no impact to any corals, inverts, or fish. I did get temporary ORP drops (~450 -> 200) that would rebound over several hours, and zoas would close up for an hour or two.
Parameters today are all the same except temp is now steady at 78 deg thanks to cooler weather. No sign of cyano.