I have a 125 reef and 55 fowlr
and I have coraline algae in both tanks. 4x160 watt vho
in reef and 2x 40 watt in NO
on my 55.
If you want coraline you will need to dose your tank with calcium and alkalinity.
I use the 2 part b-ionic and it is great stuff. Are you adding anything to your tank and if so what are your levels at. I have only dosed a few times in my 55 and I have coraline on 60% of the LR
and 10% of the glass. I'm not too worried about it in my 55. Wit regular water changes in my 55 it should get enough of what it needs to keep growing slowly.... Good luck..... I argree about too much light is not the right answer.