Cyanobacteria within substrate - should I be concerned?

[Chris_Homan]

I had a small Cyanobacteria outbreak which I thought I had treated successfully. However, I can see through the front pane that there are still Cyanobacteria lower in the substrate. Is this something to worry about?

 

[tam]

Tape a piece of card along the substrate, that will block the light and knock out those last bits - leave it for a week or so. You can also, carefully not to scratch the glass, use a credit card to run along the front edge and syphon it out. It will only be along the glass as it needs light.

 

[HarrietHippo]

Can also spot injection Flourish Excel if you like as well to eradicate

 

[bazz]

Tape a piece of card along the substrate, that will block the light and knock out those last bits - leave it for a week or so.

This didn't work for me either, seems the light is refracted down within the glass itself and was still illuminating the outer edge of the substrate.
Fortunately for me it never breaks out of the substrate.