What kind of light do you have in your refugium. They light should be at least as intense as your display lights. If your running a cheap light you refugium will not be able to out compete the strong lighting in your tank. I run the same lighting in my refugium but have it set for longer and at a more intense setting 50-60% display 100% refugium.
1st Upgrade your refugium light.
2nd buy a lot pods. They will eat left over food , fish waste, algae.
Add phyto plankton and reef enhance if you want the population to grow fast. The phyto will also consume nitrates. The reef enhance will add planktonic bacteria also helping the nitrogen process. My tank has no mechanical filtration of any kind the refugium is my only filter. If I turn my pumps off you can see the plankton in the water. Nitrate and phosphate are undetectable. Just ordered 2 gallons from rusalty.com due to I have to move my tank from one house to another and will be loosing a lot of zooplankton in the move. Watch this video. If you can watch all 10 episodes. https://www.bulkreefsupply.com/content/post/biome-cycle-ep9-copepods-wipe-out-reef-tank-uglies
1st Upgrade your refugium light.
2nd buy a lot pods. They will eat left over food , fish waste, algae.
Add phyto plankton and reef enhance if you want the population to grow fast. The phyto will also consume nitrates. The reef enhance will add planktonic bacteria also helping the nitrogen process. My tank has no mechanical filtration of any kind the refugium is my only filter. If I turn my pumps off you can see the plankton in the water. Nitrate and phosphate are undetectable. Just ordered 2 gallons from rusalty.com due to I have to move my tank from one house to another and will be loosing a lot of zooplankton in the move. Watch this video. If you can watch all 10 episodes. https://www.bulkreefsupply.com/content/post/biome-cycle-ep9-copepods-wipe-out-reef-tank-uglies