Free macro algae id?

[Crash]

I got some free macro earlier today, im just not sure which plant this is... it looks like my halimeda algae in my fuge section but its alot bigger and less color (probably because it hasnt been under a light for 8 hours).

Here is a pic of the new algae being quarantined untill I can figure out how to get rid of the Aiptasia infestation (any suggestions on how to rid these guys and not kill the algae?)

Any idea if this is for sure a halimeda? Also, I cant find a base with this one. How should I go about planting it?

Here is a picture of my current algae:

Any reason why the chaeto I got for free looks so much different too? The "strings" are so much thinner than my current chaeto.

Sorry for the 1000 questions I've had the past couple days. You guys are a great help everytime (I've become dependent lol)

 

[MacDracor]

Many common names we use are not species level. There are numerous species of halimeda, for example. While whitish halimeda is usually dead, I'm reasonably certain that the specimen you showed is indeed halimeda.
For aiptasia control, many have success with peppermint shrimp, though for a major infestation I recommend berghia nudibranches.
Same with chaetomorpha. There are different varieties.

 

[Crash]

Many common names we use are not species level. There are numerous species of halimeda, for example. While whitish halimeda is usually dead, I'm reasonably certain that the specimen you showed is indeed halimeda.
For aiptasia control, many have success with peppermint shrimp, though for a major infestation I recommend berghia nudibranches.
Same with chaetomorpha. There are different varieties.

Thanks, I didnt know that before. My other halimeda turns white while the lights are off but regains color after a hour under the light. Is this not normal then? Am I stressing the plant out with too much light/flow or not enough?

 

[MacDracor]

While the individual species may have different preferences, I'd say try to give them roughly the same care and see how that goes. Remember, these are algae not plants. They're usually pretty resilient so it just depends on how much damage occurred in shipping.

 

[MINItron]

Thanks, I didnt know that before. My other halimeda turns white while the lights are off but regains color after a hour under the light. Is this not normal then? Am I stressing the plant out with too much light/flow or not enough?

Halimeda is a calcified algae. It can do some strange things some times like the turning white at night. I wonder if it has something to do with it laying down calcium.