Purple Tipped Across Slow Whiting from Core

[jdhoover]

Hi,

I have these purple tipped acro's, several colonies of the same thing - for 2.5 years I've been propagating them in this tank. Over the past 3-4 months they've slowed their growth and starting whiting out from the core out. They are not bleached out dead - still have active polyps down in the white. Everything else (20+ species of coral) are doing fine, but these acro's are hurting at all spots in the tank.

Data: Apex Controller. Phosphates, 0.00 via Hanna. nitrates 1.0. Temp maintained 78.1-78.9, pH 8.1. PAR at 200 (near this colony) peak for 9 hours, lower level PAR for 2 additional hours. It hs always liked that level PAR. Salinity 34.5, dKH 12, Calcium 410. Regular water change via Apex DOS. Feeding is a mix of calanus, reefroids, mysis, oyster feast, flake food.

My guess is not enough feeding - I have really stepped it up to twice a day a lot of variety with target feeding, from every 2-3 days (and no target).

 

[jdhoover]

Any other thoughts on reasons for whiting out from the core out, but still polyps, and not fully bleached - and only the one coral type.

 

[outssider]

shading ??...are you running 100% L.E.D.

 

[jdhoover]

Not shading - these five colonies have clear access to the top of the tank. New info: inspected closely and found three asterina star on one of the cores that is in trouble. Hmmm...

 

[mcgyvr]

Not shading - these five colonies have clear access to the top of the tank. New info: inspected closely and found three asterina star on one of the cores that is in trouble. Hmmm...

My experience shows that asterina stars don't cause trouble.. But they will certainly feast on a coral thats already in trouble.. They are scavengers basically..

Many people are finding that with low nutrient levels that they can't maintain the high alk like you are running..

 

[Piper27]

I second that asterina comment. Except for a select few situations.

You alk at 12 and nitrates at 1 and po4 0 is not helping you. If the change happened slowly over weeks then I would say nutrients are too low. How long have you ran the tank with alk around 12?

 

[rvareef]

+3 asterinas are not the cause, they are just cleaning up the mess,
my guess is lack of food/flow/light or alk/temp swings, also could be acro parasites if you did not quarantine

 

[jdhoover]

Anyone have other posts or docs I can read on the high alk and low nutrient badness - that’s a newer one for me. I’ll bring down the alk to 10 over the week.

Good to hear on the asterina - they had never caused a problem in the past, but makes sense they were on the coral as cleanup, not likely the cause.

 

[jdhoover]

Been running that way alk-wise for a year. But had been cutting back on feeding, and I think i got too low. The whole high alk and low nutrient being a problem is a new one for me - definitely gotta read up there.

 

[mcgyvr]

I haven't really seen a single article on the low nutrient/high alk issue.. Just multiple peoples reports/what worked for them..

Don't lower alk too fast.. Slowly let it drop over the next few weeks.. Slower the better.. Don't want to stress it anymore..