Sand Clumping

[Buck commander]

Hello - Any idea on this sand bacteria? Been in the hobby for close to 10 yrs. This tank is close to 2-3 yrs old so assuming way past the cycle stages. Guessing cyno or something similar. Been adding GFO water changes etc... lights are LED still no change.

 

[lapin]

Not sure on the clumping issue. I never had clumped sand.
The green does look like cyano. I have it.
It comes and goes.
More sunlight (summer) it comes
Less (winter) it goes away
For me its seasonal..... Like tree leaves turning gold in the fall
GFO and water changes do not effect my cyano at all.