What kind of algae is this?

[Fresh2o]

Day 4 of treating Cyanobacteria with erythromycin (is that ER or EM?)
Prior to treatment I siphoned about 90% of it out. Either missed some spots or they were stubborn.

From what I can tell, it's not coming back but it's not quite going away yet. There's one more dose in the 10 packet box. Thinking I might get a second box and dose for and additional 5 days.

Been reading up old threads on the causes of cyano or conditions that are conducive to its growth and reasons include:
Low water flow, low Nitrate, low CO2, excess light

 

[Rivercats]

It can still continue to die off even after treatment so personally I'd hold off a week and see if it finishes going away. The couple times I had to treat for it I never had to do a 2nd round of Erythro.

 

[Fresh2o]

Spot on, Rivercats!
A day after the last dose the cyano is continuing to "disappear". The next water change is this Friday or this weekend so hopefully there is enough erythromycin in the water to kill the any remaining cyano.