Cyano problem, need help

[125mph]

I have been battling cyano for about 9 months and not sure what to do.

- Ran chemi-clean 4 times, and it keeps coming back
- Ran coral snow + cyanoclean and it did nothing

My nitrates are around 5ppm and phosphate around .04ppm, but phosphate stays stable and nitrate drops by 1ppm per day and i dose another 3-4ppm every few days to keep it from crashing. AI thinks its an imbalance of nitrates dropping too fast and has me dosing 1ppm per day to keep it stable. Trying that now.

Running a skimmer, turb scrubber, and fleece roller (reefmat).

Tried lots of water changes, cleaning sand bed. Nothing works

 

[EnterName]

It might be the light but the substrate looks "rust"-colored or brown rather than the typical dark purple slime mat that can be siphoned off easily.

To me it looks more like a severe diatom issue. The actual Cyanos I can see are down in your substrate where you can see a red/purple discoloration, but that's not necessarily an issue:

This for example is (a far less severe) Diatom issue:

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If you have access to a microscope or know someone that has one, I can suggest taking a sample and looking at it at 200x or 400x magnification. I can help with the identification if you don't know what to look for.
You can also check out my microscopy thread's posts on diatoms (page 1, post #16) and cyanobacteria (page 3, post #52).

Another possibility are certain benthic dinoflagellates, but those tend to produce slimy mats rather than rusty "dust" on the substrate.

 

[KrisReef]

I also think that these mats may be something else?
But for Cyanobacteria-

This is supposed to work, but it takes a while and a few consistent treatments to get to where you want to be. Since you have tried Chemotherapy many times, this may be the way?

The only other thing people recommend is increasing the amount of flow in the tank.

https://www.reef2reef.com/threads/e...no-eradication-made-easy.916381/post-10283431