Why you should be running a refugium counter clockwise with your light schedule!
Refugium's can be one of the best methods for nutrient export and tank stabilization if setup correctly! I'm going to tell you exactly how to setup your refugium to see the best success for your system! The main reason we use refugium's is because they do a great job at absorbing excess nitrates and phosphates. This is because the macroalgae absorbs these nutrients and utilizes them to grow. The first simple mistake people do is design their sump so that the refugium is after the protein skimmer compartment. This is wrong because you want the macroalgae in your refugium to get first selection on the fresh nutrients coming down into the sump before the protein skimmer strips most of the nutrients out of the water column. Moving your refugium to be before your protein skimmer is a simple fix that will significantly increase your macroalgae growth rate. The second thing you are probably doing wrong is your refugium light schedule. Your refugium light should cut on an hour before your tank lights cut off and then cut off an hour after your tank lights come on. Your refugium light initiates photosynthesis meaning your macroalgae starts to use the light to make food. During photosynthesis the macroalgae removes carbon dioxide from the water, which in return elevates the ph in your tank. This essentially stabilizes your ph during the overnight dark hours when normally your ph would drop due to all of your corals and other animals respiring. We all know stabilization is the key to a healthy reef tank. To put this into another perspective say you run your refugium light on the same schedule as your tank lights. You will have a great stabilized ph level throughout the day, but as soon as your lights cut off you are going to have a significant drop in ph about 3 hours into the night due to everything in your tank and sump respiring at the same time. In conclusion you SHOULD BE running your refugium light COUNTER TO YOUR TANK LIGHTS with an hour overlap for your tank lights cutting on and off. Comment below with any questions and tell me what schedule you run with your refugium!