unwanted algae

[dancingpig]

tank dimensions follow

Three weeks ago I upgraded the lights on my 75 from two flourescents to two VHO (1 daylight, 1 actinic) Obviously, the growth of algae increased, but is limited to primarily green algae. The problem is two things:
1. I cannot get my coralline algae to grow at all.
2. I have various small patches of brown slime algae on my
live rock. This same brown algae (which I am pretty sure is actually diatomaceous) spreads really fast on my crushed coral substrate, but doesnt really spread on my live rock. How do I prevent this spreading on my substrate?
I am planning on adding some easy to keep corals (leather, mushrooms, star polyps, etc.), but would like to get a handle on this problem beforehand. I have added ten astria snails, and two red legged hermits. This brings my count up to about twenty astria and fifteen hermits, do I need more? Will they eat these problematic algae? I haven't been adding any supplements except calcium, would Coral Vital make a difference? Any help would be greatly appreciated.


75 gallon
1 cpr bakpak, 1 seaclone, 1 HOT magnum, 3 powerheads for water movement
dual bulb VHO (actinic, and daylight)
70 lbs live rock
various polyps and mushrooms
9 in. volitan lion, 5-6 in koran angel, 4 in. purple tang
I only feed the lion twice a week, and I feed the other two a half cube of frozen a day. (spirulina brine or emerald entree)
water changes of about 12% every two weeks, should these be larger?

 

[VoodooChild]

How long has your tank been set up? Diatom blooms are common in the first few months. You have plenty of inverts. Remember that if you have enough to totally wipe out the algae, you'll have lots of little bodies lying around from starvation. I'd maybe do 25% every other week. That should keep things going. If you're dosing calcium, that's about as much as you can do for the coralline algae, but you may have some invert that's eating it. Anything else in there?

 

[dancingpig]

I am pretty much positive that nothing is eating my coralline, unless choc. chip stars eat coralline....they don't do they? My tank has been running for about 3 years.

 

[kreblak]

If you've been up and running for 3 years, then it is really hard to say what the source of your brown algae is. My hermits love picking algae off my live rock, and playing king of the hill at the same time. They keep my crushed coral churned up and clean, too. With 15 in a 75 gallon tank, you should be all right. Maybe try adding some blue legged hermits. Just get small ones that wont go after your snails.

The reason that your corraline algae isn't growing might be because the nuisence algaes are taking the available nutrients from the water before the corraline has a chance get them.

 

[dancingpig]

since I added the last ten astria's their has been obvious improvement on the rock, but the substrate (crushed coral) continues to grow the same brown crap. What are my options as far as getting rid of this substrate goo? I could add a fish to keep the c.c. stirred up, but I already have what seems to be a pretty full load. What would be the best invert for a job like this?