The cross section of your sandbed pic fulfills nine pages of information in the sand rinse thread as to why making that bed cloudless will stop the cyano in my opinion. We aren't using oxidizer in the thread much at all to get the posted results.
Dirty tanks in, clean out, the thread shows other people's $ on the line.
Peroxide is not ideal for cyano, I never recommend peroxide for it as treatment due to low returns in the long running threads. Not high enough cure percentage to continue although for sure bubbly is indicated in many other invasions imo
A cloudless bed will do it.
I'd prefer to have this red mat situation over dinos, gha, bryopsis, it's fixable
The growth does not present 100% on rocks and sparsely on the bed as overflow, it presents in the reverse indicating the locus/feed zone I bet. completely natural hitchhikers who also will get in again...all our tanks...they found niche support here and a manstorm w fix it
https://www.reef2reef.com/threads/t...ead-aka-one-against-many.230281/#post-2681445
Of all the invaders even weak undermatched UV is likely to prevent, id rate this one as no 1 for a totally opposite means. Pair the two, seal the deal. Sand rinse technique + correct UV for your large tank? Never invaded sand again.