The following marine algae species are a great choice to keep them in a Sump / Refugium, with an extra refugium light for them to grow. They are the first choice when it comes to reducing the Nitrate and Phosphate levels by exporting Nutrients through their growth in the reef tank, fish only aquarium or seahorse tank, as they grow very fast.

Beside the by far most popular macro algae Chaetomorpha / Chaeto, many of the other listed Caulerpa macroalgae species are amazing fast growing macroalgae and just perfect for the Nutrients export from the marine aquarium. As they can be quite invasive they are best placed in the restrained area of a marine Sump / Refugium area.

If you have a typical Refugium / Sump setup with 3 chambers we would recommend to use the middle chamber for the macro algae, so the parts with the return pump/protein skimmer will stay algae free. As well we recommend using a coarse filter before the last chamber. so no macroalgae can enter your tank display.

Beside the great advantages of reducing the Nitrate and Phosphate Level in the marine aquarium, they will as well provide a perfect environment for Copepods and Rotifers too and help to increase the population of those beneficial cultures.

Surely it is possible to add almost all of our marine macroalgae we offer to the Sump / Refugium, but we would recommend much more the mainly macroalgae species below, as they will grow faster, which means they will more effectively lower the Phosphate / Nitrate levels. 

Red Macroalgae species could be placed in the sump/refugium of course too,  but they grow often much slower than the green macroalgae species, and in our opinion they are almost too beautiful to hide them in a sump/refugium. Of course in an open refugium/sump tank as a planted refugium show aquarium they will be brilliant to use again :)