My musings - purely from observation :
My first tank - a 30 gallon - aragonite gravel substrate - never any cyano
My daughters first tank a ten gallon nano - also aragonite gravel - never any cyano
Upgraded my tank to a 90 - used live sand instead - huge cyano
Upgraded my daughter's tank to a 20 - used live sand instead - unbelievable cyano
After a tank crash while on vacation, I came home and completely broke the 90 tank down and reset the system, this time with crushed aragonite gravel and crushed coral. No sign of the cyano
Nothing else has changed. As stated - purely observational data, but I am really wondering if there is a connection.
I have read a few articles and almost always there is the mention of cyanobacteria growth with smaller sediments such as sand , silts, and muds. I suspect that the cyano
rides in with the live sand.
Perhaps there is a connection between the amount of water flow between particles and the ability of the cyano
to gain a foothold. Perhaps the sand particles do not get moved around as much as they would in the ocean environment allowing the cyano
to "cement" the topmost layer of sand in place as it forms mats, thereby reducing the flow of water even more. Without the water flow between particles, the food and waste that support cyano
would not be broken down as quickly, thereby fueling the cyano
growth. This leaves us with the task of finding ways to reduce the amount of fuel as well as finding a way to keep the flow between particles as high as possible.
The chemi - pure type products are oxidizing agents which help break down the organic compounds that fuel the growth. This is why they are considered temporary fixes, rather than cures. If flow rate is indeed a factor , the chemi-pure does little to help that problem.
Again - only my musings.......
Best of Luck