This brown leafy algae is Sargassum. Some have allowed it to grow in their main tank, but it can get quite large and unslightly. Typically arrives as a hitchhiker on live rock or coral bases, but doesn't seem to live too long in our systems.
I was given this red macro algae, and was told it is Red Chaeto(morpha). Since its prickly structure looked nothing like Chaetomorpha, I contacted a few algae experts for help. What it actually is is Caulacanthus ustulatus, but what matters more is knowing that it is an invasive species that we do not want in our tanks. It breaks up very easily into tiny pieces, and takes root anywhere it lands. Fortunately for me, it didn't live long in my refugium. Not Reef-safe, nor refugium safe.
This algae is referred to as Maiden's Hair. It is lighter green than the more common Green Hair Algae. This algae seems to grow more like a tall lawn, with uniform blades. It could be plucked out by pinching it off at the base, and comes of quite easily in my experience.
This algae is called Dictyota. I saw it on a coral at the local fish store. It can be recognized by the way its leaves split. I've never had it in my tanks, so I can't offer further information. If you have additional information, contact me.
Check this out: Neomeris annulata in abundance!! Never have I ever seen it in a tank like the picture above. Usually you'll see at most five sprigs of this calcium-based macro algae, and it tends to only live a short duration. Ryan has so much of it growing in his reef that he's giving it away. He even posted a picture of a snail on the glass with Neomeris sp. hanging off the shell like an octopus. Amazing. Reef-safe since typically you'll never see more than a handful in your own aquarium.
Photo by ryngill
Macro algae is a way to keep nitrates down in a reef tank, and many grow it in a refugium. Although illegal in some states such as California, Caulerpa racemosa has grown well in my refugium, and needs pruning every few weeks. As you can see, it has a distinctive look you can quickly recognize and some refer to it as Grape Caulerpa. I've found that it will not go sexual (and disintegrate) if the light is kept on 24 hours a day over this plant.
This algae is Lobophora, a type of encrusting or plating algae. Probably Reef-safe, until it grows out of control. Some tangs will likely feast on this. Notice besides encrusting on the rockwork, it has some curling plates forming on the leading perimeter.
Photo by Slinger
Macro algae is a way to keep nitrates down in a reef tank, and many grow it in a refugium zone. Although illegal in some states (such as California), Caulerpa nummularia grew well in my refugium, and needs pruning every few weeks. I've found that it will not "go sexual" if the light is kept on 24 hours a day over this species. The above shot was taken where this macro algae grew tightly and densely on the substrate and rockwork. It sends out vines in every direction taking root in the substrate and rockwork.
A nuisance for sure, Bryopsis is a weed that has frustrated many hobbyists. Eradicating this type of algae is difficult because it anchors itself well to the rockwork. Very coarse in nature, this plant attracts any type of detritus which it then uses to create its own nutrient base substrate. Looking very closely at this plant, you'll note it has a feathery look to it which is how to identify it properly.
Solid blades of what appears to be turtle grass, this is C. prolifera. This macro algae would be suitable for a refugium or a seahorse tank, but needs to be pruned to encourage regular growth.