You can have so-called low (abit undetectable) nutrients in your water but hotspot for nutrients built up on the LR and sandbed. Low nutrients don't refers to getting undetectable PO4 and NO3 from your testkit, there is more than that.
Does it feel better if you have people agreeing that some algae in the tank is normal?
Cyano does exist but in what proportion? One big patch here and there? or they are present but not in big porportion that can be seen easily?
Blueheaven, same goes for the big patches of green algae on your LR. Like I said, if you think that is fine then it's fine for you but IMHO, that's too much algae. Or you want to wait till a tank turn into marine planted tank then says it is excessive algae?