Multipl coloured algaes id

[Piece of reef]

Hey guys
Had my tank running for almost 6 months now

Parameters are
Ph 8.0
Ammonia & nitrite 0
Nitrate 10
Phos 0.13 ( working on it)
Salinity 1.024
Alk 8.5 dkh
Calcium 420
Mag 1275

All tests done with hanna and salifert

Anyways ive had light green algae show up a month or so ago and you can scrub it off the rocks
But also have this purple colour growin on the glass under the sandbed
And also brown which is diatoms


Any id on the purple stuff ? Is it cyano

 

[PeterC99]

Don’t know what this is but hopefully bumping this post to get some answers.

 

[Piece of reef]

Oops just realised
I meant you "cant" scrub it off
i accidentally wrote "can"