Identify this algae.

[jhatfield]

Just finished a chemiclean treatment which (so far) seemed to work pretty well. No bright red cyano and the rocks look great. But, I'm left with this brown algae on the sand which I'm guessing is not cyano since it did not respond in any way to the chemiclean treatment which included a 48 hour blackout.

This stuff was there before the treatment but I assumed it was cyano. So now I'm guessing diatoms.(?) Not only was it not affected by chemiclean but was unaffected by a fluconazole treatment I did for bryopsis a few weeks ago.

 

[SDReefer]

Diatoms. Usually grows due to the presence of silicates in the water. Are you using RODI water for your topoff?

 

[jhatfield]

Diatoms. Usually grows due to the presence of silicates in the water. Are you using RODI water for your topoff?

Yes, using RODI for top off and for salt water mix.

During the cyano bloom nitrates dropped to around 2 and the phos went undetectable using hanna low range phosphate checker. This brown stuff seemed more than happy to have nutrients in that range.

 

[SDReefer]

It looks like that your system has been put under stress by the treatments, and the diatoms may just be your tank's way of bringing itself back to normal. Maybe just test your TDS to make sure.

 

[jhatfield]

It looks like that your system has been put under stress by the treatments, and the diatoms may just be your tank's way of bringing itself back to normal. Maybe just test your TDS to make sure.

Will do! Thanks for the help.