What’s going on now?

[TiggrReefer]

Here is a picture of what is currently going on. This blanket of algae(?) or diatoms(?) or ???
And what to do about it?
I should mention 4 months with fish in a 125g; recently got red slime algae under control without by physical removal and without Chemiclean
Thanks

 

[Legendary Corals]

Is the area where the sand bed is clean where flow is being blown to? If so, your tank may benefit from more flow to help push the algae into the water column to be filtered out. Algae tends to grow on sand if the flow is low.

 

[TiggrReefer]

Is the area where the sand bed is clean where flow is being blown to? If so, your tank may benefit from more flow to help push the algae into the water column to be filtered out. Algae tends to grow on sand if the flow is low.

I just got a new MaxiJet power head which I have NOT YET installed (old one died)
I was going to remove as much of this blanket and then installing new power head.
Right track??