Is this Diatoms?

[SteveCGY]

I'm not an expert maybe someone else can chime in but to me looks like GHA covered in diatoms. Only as that's what my tank looked like at the beginning. Once my diatoms left I was left with GHA.

[Cal_stir]

I don't think hair algae will blow off, +1 on dinos.

[banditpowdercoat]

I do have a GHA issue too, but mostly at the upper levels of the tank, like overflow rim

[Cal_stir]

Ya, looks like I can see some in the lower part of the pic, are you using anything for phosphates?

[banditpowdercoat]

Only using Biopellets

[Cal_stir]

Pellets not real good at po4, might need some GFO.

[iceman86]

It looks like gha with cyano. Check your phosphstes and you can lower them them with gfo. If you use gfo slowly add it to your tank because you can shock your corals. Biopellets mostly work on nitrates, also make sure your using the right amount. Too much can strip your water.