do u guys have these in your tanks? i dont know if im paranoid but do they eat corraline? ive noticed some corraline turning white, is that bc of these guys? no coral damage as most say, just the algae
yah these stars do eat coraline alage. i try to take as many out as possible. they dont eat a whole lot but i hate to see the patches.
Asterina is a genus of seas stars which contains main different species. Some people have no problems with them, some people take drastic measures to try to remove them all. I have never had a problem with them, but I have also never had as much coraline in my tank as Brett.(which I have to say I really like the look of)
There are reports that there have been some that will bother corals however I have never met a soul in the hobby who has come across any. I will say that one of our clients had a ton, purchased a harlequin shrimp(Hymenocera pitca), and now I can’t find one in his tank. Now he is buying other star fish to feed the animal, but he could also afford to feed it anything it could possibly need.(and pay the company I work for to clean up the mess it leaves)
If you have small white spots then it could very well be the sea stars, but if you experiencing an overall white perhaps something else is the cause. The pretty purple algae you desire in your tank usually grows best with bluer light and despite what many in the hobby believe can easily be damaged with too much light. Keeping your Ca, Alk, and Mg dead on with be the biggest thing you can do to help it along. These are just my opinions from my reading and experience.
What Jon said.
But also: I always had a line of dead coralline from doing water changes. If you lower you water level in the display for WC’s the coralline will die off above the line.
the light comment you made, has me thinking…
How long do you guys keep your lights on? I keep mine on for almost 12 hours…
[quote=“michaelangelo, post:5, topic:2001”]
the light comment you made, has me thinking…
How long do you guys keep your lights on? I keep mine on for almost 12 hours…[/quote]
I think most of us leave our lights on between 10-12 hours. The issue isn’t as much how ling you leave the lights on as much as it is the intensity of the lights. A 4 bulb T5 fixture left on for 18 hours a day isn’t going to have nearly the impact as a 400w MH bulb 3 inches over the water for an hour.
I agree with Craig. It’s not how “ling” you leave the lights on as much as it is the intensity. 
Personally I think 12 hours is a bit long. Seems to grow more anoying algaes at that duration and uses more electricity.
[quote=“Gordonious, post:7, topic:2001”]
I agree with Craig. It’s not how “ling” you leave the lights on as much as it is the intensity.
Personally I think 12 hours is a bit long. Seems to grow more anoying algaes at that duration and uses more electricity. [/quote]
Really? YOU are going to make fun of typos??
;D