Why is my coraline dying?

[Mr_Cool]

It used to cover the whole back of the tank. Now, it kind or flaking off and even turning a little green.

I haven't tested the water in a while. I'm going to do that now. I was planning to do a water change today anyway. I'll post results of the water test later. Anyone want to make any predictions?

[Mr_Cool]

Well, pH and Alk are a bit low. (ph = 8 and Alk is at 2 meq/l)
Nitrates are at 0 and I didn't test anything else. (Actually, I rarely test amonia and nitrites. And, don't even have a kit for calciulm or phosphates.)

I guess I need to bring up the Alk, huh? Any ideas? I don't know if I want to start dosing kalkwasser, or start w/ a two part solution. Baking soda or washing soda should do the trick, right?

[SoLiD]

I thought I saw someone post a while back that high phospates hinder caulerpa and coraline growth. I'd check on your phosphates if I were you.

[Mr_Cool]

Well, the caulerpa in my fuge is growing just fine. IDK.

[JimD]

Lighting change?

[SoLiD]

Just because the caulerpa is growing it could still be high enough to impact coraline growth. Try a water change. They never hurt anything. -David

[Ed]

Might want to have an LFS test your water for Ca and Mg before dosing anything.

[Mr_Cool]

Actually, my actinics went out about a week and a half ago. Still haven't had a chance to test the ballast, though. I've been running 2 10,000 k bulbs and 2 18,000 k bulbs during this time. The actincs used to come on for a few hours, go out for a few and the come back on for a few more. The tank is missing about 6 hrs. worth of actinic lighting. Could THAT make a difference?

Did a pretty good sized water change just this afternoon.