Base of Montipora Digitata turning white

[AmherstReef]

The base of my Montipora Digitata is turning white at the base where it's attached to the rock. The rest seems to be going great along with the rest of my corals . Here are my parameters

PH 7.9. (A little low since we closed the windows)
Alk 9.0
Ca 380
Mg 1230

The only thing I dose is Kalk in my ATO

 

[Conesus_Kid]

Are there other montipora in the aquarium? Any recent changes in alkalinity? How long has this been happening?

 

[AmherstReef]

I have some Monipora Cap which is doing great, no changes in Alk. Noticed it a few days ago

 

[spinoleo]

have you added any coral lately? also cal is low

 

[oneradtek202]

low ca doesnt USUALLY cause STN/RTN....id look for something such as flow, chem warfare, too much carbon....ummm stuff like that. ive had STN before and it was mainly due to ALK swings, usually too low

 

[AmherstReef]

No new coral , alk has been steady

 

[magdelan]

It's unfortunate that it happened, and now moving forward, I would snap it off well above the damaged area and salvage what you can. By doing this, you will not let the whole piece succumb to tissue necrosis.

 

[oneradtek202]

low flow in the middle of the colony?

 

[oneradtek202]

It's unfortunate that it happened, and now moving forward, I would snap it off well above the damaged area and salvage what you can. By doing this, you will not let the whole piece succumb to tissue necrosis.

+1 you can try to figure out why all week, but if it continues, then id just do that as well

 

[Henry Colf]

What test kit are you testing your alk with? I would take a water sample to your local lfs and have it checked by them. I agree with Brandon, when I lost almost all of my sps last Nov. it was due to my alk bottoming out. Have you done a recent water change with a new batch of salt?

 

[Conesus_Kid]

I would also look very closely at the edges of the bleached area. I couldn't see any in the photos, but be on the lookout for tiny white things that look like rice (except much smaller). If you see something(s) that look like that, they are most likely montipora eating nudibranchs.

 

[Henry Colf]

I would also try to get your other params in line. If your alk is at 9dkh, then your calcium should be running around 450-460. If you only dose kalk and nothing else I would make up a fresh batch of sw and test it before you do anything with it. See what the batch reads. I think you might find that your ca level is really low. I may be wrong but its what I would do to see. Kalk is supposed to keep alk and ca buffered and in balance(at least thats what i've always thought anyway).

 

[AmherstReef]

Alk is definitely right I have two kits, an API and a brand new Salifert. I also retested Ca and its actually 420. I used a flashlight to try to see any nudibranch this morning but I couldn't see any thing.
I would also classify it as STN, I probably a small white area weeks ago.

 

[oneradtek202]

Lol...flow? Sometimes the middle of colonies die off due to lack of flow, only other idea, if not that...then just chalk it up to nature!

 

[Gary Majchrzak]

got any clown gobies?