Convinced of a link between GFO and Cyano (and not the good kind)

[Skim]

Well just thought I would put my 2 cents in. I had Cyno start to appear and this is what worked for me. Pull the GFO and GAC get some Seachem Purigen like 1L and pick up a few of the Seachem " The Bag" works perfect for the Media as it is fine. You can put it in the sump or better would be a small Canister or if you have an AquaClear hang it on the back or side. I did this and within the first day you could see the Cyno start to disappear and your water will sparkle. This stuff lasts quite a while and can be regenerated. It rapidly removes Organics from the water.
One other thing maybe I missed it but is your skimmer working as it should?
The other thing maybe lights old tubes or bulbs if you are use them.
Give the Purigen a try, its simple safe.
The other thing I just thought of that seem to help also was Brightwell Aquatics-Microbacter 7, with a large tank you may need to get the 2L bottle.

Good luck.
All the best.

Mike
P.S one other thing you can try if you use the Purigen is cut back the lighting time or shut them off for 2 to 3 days. That should get ride of the stuff real fast.

[asylumdown]

Yes, I'm definitely over simplifying it, as cyano has been a problem for as long as people have been keeping salt water tanks. In nature there's probably lots of cases where the nutrients needed for it to grow are present but it still doesn't, so there's a lot of complicated interactions going on. One paper I read even hypothesized background levels of hydrogen peroxide, which can naturally reach as high as 0.36 ppm in some parts of the ocean, might inhibit huge amounts of cyano bacterial growth (reactive oxygen is particularly deadly to cyano's photosynthetic structures).

You also have predators that we probably don't keep in tanks, bioturbation on a much larger scale, stronger wave action, and more things to compete with it.

I'm sure we could also find lots of tanks that deal with cyano that don't use gfo.

But, when you've got it, or are fighting it, I think it's worth considering that what has been long touted as a cure might in fact be part of the problem if gfo and low tested phosphate isn't slowing it down at all. There's good, supported science to suggest a link, and a long evolutionary history that makes cyano uniquely adapted to turning your best tools against you. In researching some background for this thread I even found an article where they assessed how good glucose and fructose were at making different species of oscillatoria grow (sad news, sugar dosers).

Fwiw, I'm on day three of phozdown dosing and I'm either wishfully seeing things, or my cyano population is down by 25%