Bleeching..

[Doompie]

Hi Guys,

Oke it seems like I have bleeching issues...I've lost most of my stoney corals in about 4 weeks time (mid feb / mid march)..without changing anything though..
They all started too bleech from the bottom up-ward, and where all completely gone in about 6 - 10 days..

All except for the caliendrum and the favites red-eye.

The favites just looks very healthy as it always has, the caliendrum has had some problems (bleeched bottom 3 cm's), but recoverd it self for some reason and descided to start growing (faster), while the others I had (acropora's and hysterix) are all gone..

Strange thing is, I never measured more then 0 GHA's..
Didn't change anything (I increased feeding since early April, that's my only change since februari)..
All corals are growing..

My reef is about 6 months old now.. dairy can be found on the forum..

From Februari the SPS colors faded, and never came back they where before..

Currently there is only 1 piece of acropora left, which mostly has been bleeched..polyps which are left, are colored darker, but do extend.

Seems like I lack the magical SPS formula..
All other corals I keep are doing fine..

Please help me out here..Thanks in advance..

[Ace25]

Need more info on your parameters. I just looked at your build thread and one thing that stood out is your display lighting. Are you still running 10k/20k combo? I really think you need more 420/455nm on your display. I would replace a 10k and a 20k with a True Actinic and a Super Actinic bulb. It won't seem as bright to you, but your corals will pop more and get a better spectrum of lighting. That is the only thing I can think of off the top of my head without knowing the parameters of the tank.

What you are having happen is commonly called "STN", slow tissue necrosis, which happens over the course of a week to month, where as RTN, rapid tissue necrosis happens within hours. There are many theories on the cause but nothing certain, the cause could come from different issues. Some say it is a bacterial infection, others say a water quality issue, others even say lighting related.. all or none could be correct.

[Garf]

Doompie - as ACE25 sais it could be 100 different things. Here's another option - I have been examining your photo's on your tank build thread and something doesn't look right with your frags when you received them. A couple are degenerating and the other is puttied on to a rock. Starvation of these corals is a major problem. Perhaps a bigger problem is that when a large coral shows signs of basal tissue necrosis, this coral can be fragged and sold on as healthy. However, the whole coral is weakened by starvation and often dies. It may not be your tank conditions at all !!

[SantaMonica]

Sounds like what happened to me this summer... 93 degrees F water temperature, killed a third of the corals.

[Doompie]

Thank allot for the input so far..
I checked over the parameters every week and really never measured any N or P, tested both with JBL and Sera. Ca and Mg and Ph are all just fine. Also the Temperature is very stable on 25-26 degrees celcius.

Most of the small ones I indeed blame on too weakend / low quality frags..

The digitata did grew nice and steady, but was attacked by a traveling glass anemone (on a crab shell)..so that's just sad..(or poor maintenance:S)

But got a very nice pinkish acro which now is on it's last breath..that I cannot yet explain.. must say, since I've increased feeding and optimised the lighting period for my tank combining T5 and LED, the process slowed../stopped..is think an option is outflowing P's because the seaweeds where flourishing a bit on the former deathrock for a month or so. Though the test sets did not measure P's..there probably where releasing from the former deathrock.. Now since end February the tank is almost clean from weeds, and currently there are just a few small leafs. Also the coralline algae and macro life is flourishing as posted, which also hints on good water parameters..

Will change the display lighting soon. Considering to change too your advice Ace and too change another 10.000k for a 14.000K before I try again..

Now we are on the acro topic.. what do you guys think about the DLI theory?
According: http://www.advancedaquarist.com/2009/5/aafeature

Since the ATS environment is much richer than skimmer systems, does the Acropora balance it's feeding between light and polyp feeding?

[Garf]

Can we see a pic of this pink acro. True bleaching is just an expulsion of the algae within the skin tissue and can be replaced with other species that meet the coral requirements in some cases. The death events mentioned above are tissue death related.

[FrozenReef]

Like others it could be any number of things.

However, too things come to mind when there is slow recession from the bottom up. If your alkalinity levels have been too low for quite some time it becomes a limiting factor in calcification. Conversely, if your alkalinity levels are too high based for your nutrient level. When your running low nitrate/phosphate levels the higher you keep your alkalinity the more likely to see recession near the base. Best to keep it around 7.5 dkh - 8dkh. Just high enough that if your testing is off a little your still have some breathing room before calcification is limited ( ie: < 7dkh ) but not too high to cause recession from running lower nitrate/phosphate levels.

Iv'e been an SPS/Acro lover for going on 16 years now. Anytime I see any signs of tissue recession at the base ( not rapid but slow and steady ) , my Alk levels have drifted a little too high, bring them back down closer to 7-7.5dkh and starts to regrow tissue at base again.

[kerry]

And here I was worried when my Alk got below 10!!! Does anyone else run a low dkh? I have some hard corals so alway tried to keep it up. However I found that I can not keep Long Tentacle plates and Lobo's, I can keep a pineapple brain coral though. Any my birds nest seems Ok with my higher dkh.

[FrozenReef]

Natural SW levels is 7dkh. So I don't really consider that as being low. When your running .02ppm or below phosphate levels, ALK other than 7-8dkh it can be an issue. When your not running that low of phosphates and your not seeing the symptoms ( recession starting at the encrusted part of the acros/sps ) then running higher levels can be fine for your system. There is no real benefit or reason to though especially if your running your supplementation is automated. The key is not to let it get below 7dkh as that becomes a limiting factor in calcification. Some will say they run higher becuase of pH issues but the main variable to pH in our systems is CO2 levels which high alk will not resolve. Good thing for algae scrubber users is the CO2 levels are not as much of a concern since it's getting consumed.

Keeping long tenticle is no real correlation. They just have very low long term success rate anyways and should be avoided.

[Ace25]

To be honest, I always had the best luck with SPS corals by keeping Alk at 5. Everyone said I was crazy keeping it that low but I always had the best success at 5. Whenever I try and maintain it in the 7-9 range I run into issues, I would neer run alk above 9 myself, but I know many people keep it at 11 and say it works fine for them.

3+ years at keeping Alk right at 5 and this is what my tank looked like. SPS corals grew insanely fast, actually too fast for my liking. Seemed like every Saturday was "frag day" and I would fill up 2 racks full of frags.