Zoas are bleaching/dying, HELP!

[Saltwater gardens]

Some of my zoanthids are not doing great, they are not growing, opening, and some are bleaching. The funny part is that they were doing great 4 weeks ago, then started to bleach day by day, they still open (most of the colony) but no getting there color back. That same problem happened to my "Papaya clove polyps", they were doing excellent, and the same problem, they stop growing, reduce the size of their tentacles and started to get a pale color. But the rest of my corals seem to do well, or at least I think so. I really want to save my zoas and clove polyps, and get those amazing colors they had before, so guys I NEED HELP! Please.

Sorry for the picture, I'll upload a better one. But the zoanthids that are no doing great are in the inferior right corner, the first three frags.

The same zoanthids four weeks ago. And in this picture the zoanthids have some algae, but the algea is completley gone by now.

 

[reefwars]

Running a po4 remover?

 

[Saltwater gardens]

Im running a scrubber with a photoperiod of 10 hours, and my protein skimmer Reef octopus BH-90 for a volume tank of 300 liters.

 

[reefwars]

Looks like the algae is dying off fast for you if that's the case a fast drop in po4 would cause some bleaching and shrinking and even melting for some. Do you test for no3 and po4?

How mature is the scrubber? Has it been running a while or just getting going?

 

[Saltwater gardens]

I started this frag tank 13/june/2014. I'd been running the scrubber since, and by the first two weeks of december the algae (Bryopsis sp) was completley gone. Also, since june 13 of 2014 I was running a DSB of 13 inches, but again, by mid december I started noticing some black spots throug the glass. So I did a research about black spots in DSB's, turn out that it could be hydrogen sulfide. January 5th I decide to remove my DSB, but before that I added 7 propagules of mangrove (Rhizopohora mangle) on december 4th, and they are doing great. Also in my sump I have like 25 branches of Halimeda sp. and 4 branches/frags (I dont know how to say it) of seagrass (Thalassia testudinum) that were added on october 2nd.

These are my current parameters:
Ca - 415
Mg - 1320
Kh - 2.9 meq/l
S.G. 1.026
Temperature - 26 - 27 celsius
PAR (that zoas are getting) - 109 u-mol/s/sqr-meter (thats the highest peak PAR they recieved during the day, because they star the day with a PAR value of 13)

And I dont test my NO3 and PO4, any thoughts?

 

[reefwars]

Par of 13 isn't much maybe that's why the algae seems faded and cause of bleaching

Edit* ok sorry 109 that's better but can be higher

 

[reefwars]

As well fresh cut frags tend to lose color for a bit

 

[Saltwater gardens]

Exactly, I thougt the same, so I increase my Radion by 5% the first week of december, nothing happen they were happy. But still, the highest peak PAR thet they were getting was around 145. Then four weeks after (the first week of january) I increased the lighting another 5% and they were getting around 173 of PAR. And then the problem started, so I decided to go back to 109 on january 18.

But still, 173 of PAR is not high enough to burn coral tissue, right?

 

[reefwars]

I wouldn't think so I'm sure there's more to it then that though , for example I have 12" of water in my frag tanks and corals are about 2 to 3" below water and running 80w t5s so getting plenty of juice I would think however your on the right track it's usually lighting or nutrient related

 

[M3ace9]

Exactly, I thougt the same, so I increase my Radion by 5% the first week of december, nothing happen they were happy. But still, the highest peak PAR thet they were getting was around 145. Then four weeks after (the first week of january) I increased the lighting another 5% and they were getting around 173 of PAR. And then the problem started, so I decided to go back to 109 on january 18.

But still, 173 of PAR is not high enough to burn coral tissue, right?

It can be enough if not acclimated properly. Often it is forgotten that LEDs produce hot spots that will be too intense in some cases for the corals within their path. To fix this you can install wide angle lenses to help with this issue be aware with placement.

 

[Saltwater gardens]

But its curious, because they were doing fine for six months, before I increase the light output. And during that time they were never move to another place in the tank. It could be that they didnt acclimated properly, right?