Algae type....wanted or not ? Identify !

Have your lights over your refugium set-up so that they go on as soon as your lights on the main tank go off-thus constant lighting is produced to curb the sexual reproduction that usually takes place every 3-6 months(cycle) for most species! If your caulerpa goes sexual, a sudden and potentially dangerous amount of sexual gametes can be released that can harm other life forms not to mention, it can also be responsible for the notorious whole tank "wipe-out"!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Caulerpa is invasive and grows fast so prunning will need to be achieved. Many species of caulerpa contain antipredatory compounds thus many herbivors will not eat it so mandatory manual prunning will be necessary!
With the use of caulerpa in your refugium, I would strongly recommend that you perform small water changes weekly and use carbon to remove and dilute the noxious discolorants and exudations, as well as improve the overall water quality by replenishing vital minerals and trace elements to your water column!!!
Hope this helps

 

I would agree with what Coralreefer said but I also use a RDP and I like to kick my fuge light on about an hr earlier then my main tank lights go off that way the plants get a little wake up call and are at full swing and ready for business. Theni I have them go off about a Hr after the manin lights come one . Just my opinion But yes you have to run a RDP Reverse Day Photoperiod

 

Thanks a bunch for the input. I think I am putting way to much flow over the refugium so I may rig up something to pump the water past the refugium so I can still have good flow in the sump. I will have to do some engineering on that. New at this so I will definitely learn from my mistakes. Thanks again Guys!