Corals Dying
 

My tank's been running for about a year now, and lately some of the corals are dying.

My Merulina plate coral started turning white on the edges and it has been slowly creeping across the coral; now it's almost half dead. I tried scrubbing the algae growth on the skeleton but it doesn't seem to be coming off. I dose Calcium regularly but I think there may be another problem. Corals don't seem to thrive in my tank with the exception of a Donut coral and a Scolymia :(

I'll post my water parameters tonight.

Any wide guesses as to what's happening or does the "whatareyourwaterparameters?" always apply?

Thanks in advance,

Marco

What kind of lights are you running?

I'm using a 36" 4 bulb Tek Light.

It doesn't seem to be an improvement from my crappy Coralife T5s.

However, the spectrum is very blue from the 2 actinic bulbs and I'm wondering if I should have three 10ks/ one actinic rather than two bulbs for each.

I would propose the "What have you recently changed?" question?

What did your parameters turn out to be?

Sorry, I went out to buy new test kits just in case these older ones wouldn't work.

I did a 30% water change two weeks ago with another 10% the day after. My nitrites were coming up as 0.25.

My current parameters are:

Ammonia: 0.25
Nitrate: 0
Nitrite: Undetectable

I do regular water changes and feed moderately and try to keep Ammonia as low as possible. I've had this tank for almost a year now, shouldn't ammonia be undetectable unless it was a spike? All my fish are fine and swim around happily. There's no odd behaviour (e.g gills showing) of any sort.

0.25 ppm ammonia is a potentially deadly spike if accurate. Re-test immediately.

Have you lost any fish lately? There may be something rotting away in an unseen corner.

Ca and Alk levels would also be helpful.

I haven't lost any fish lately; they're all very healthy.

My Ca levels are around 450 and I don't have any Alk measuring kits.

However, there is some detritus accumulation in one corner of the tank - I didn't think much of it because I usually siphon my tank very clean every time I do a WC.

Have you implemented a phosphate reactor or anything lately? Anything that could potentially initiate an algae die-off?

I could test your Alk for you if you lived nearby....or someone else could if they live nearby.

You just changed your lights about a month ago, you posted about that, didn't you?

Why not try changing back? Obviously that change is the only major thing youv'e done on your system.