My experience with coralline algae:
You need to ‘seed’ your tank with a couple of different varieties, they can come on mature frag plugs or rock. You can also speak nicely to your local fish shop and see if they can spare a little chunk (where I work we always handing out plugs, rocks covered in coralline for peoples new tanks).
Coralline algae needs stable parameters and you will need to monitor Alk, Calc and Mag carefully. I noted that particularly magnesium gets used up very fast in the initial growth stages and can need daily monitoring for rapid drops. At one point my tank was consuming a extra 80ml a day or magnesium but this eventually levelled off to just using the 2 part dosing I was already using.
Coraline algae like a correct elevated pH. Mine grew way better at 8.2 and 8.3 and I had slow growth when it was at 7.9 to 8.0.
Coraline algae likes light, I’ve found it grows best in areas of higher PAR, but is not that fussy about spectrum, my sump has a outdoor floodlight which is very ‘yellow’ and it’s loves it as much as the more ‘blue’ light of my display.
Once it’s established it prevents nuisance algae from taking hold. It also gives off amino acids which allows settlement of beneficial critters and even coral larvae and is a great indicator if parameters have fluctuated, reacting faster than most corals to Alk, Calc or mag drops, it turns white!
This tank was only set up about 3 months ago, i transferred all my live rock and coral from a previous tank and coralline just loves it in here.
