SPS issues... again.

[ScubaSteve]

Are you running ULNS?

[doch]

Yes, full Zeovit.

[ScubaSteve]

Ok, this is just my opinion here, so take it with a grain of salt...

ULNS keep corals "trim and fit" to keep those nice colours, meaning they have little "fat" (aka excess zooxanthellae) to help them ride out system disturbances. With ULNS, we are essentially keeping them on the knife's edge. This is why so many people in the beginning of biopellets were having recession problems: the corals were starving.

The dramatic change in lighting conditions (not just intensity, but spectrum) probably caused the SPS to freak out a little while adjusting. You didn't spike the lighting, so it's not shock, but being at the intensity you are now they might not have enough zooxanthellae or pigmentation to handle the increased photons rates. This can cause photoinhibition (meaning too much light is causing them to shut down) or they're heating up at the skeletons due to the lack of skin pigmentation (ie. coral sunscreen). This can (and does) happen when you swap to new bulbs, new fixtures, etc. The change in intensity from T5 to LED is probably what triggered it. Corals that aren't pushed to the limit by ULNS can usually ride this out without ill effect.

Also, a shift in spectrum (LEDs are narrow spectrum compared to halides and T5) can cause a shift in which zooxanthellae clade is dominant in the coral. Each clade has it's own specific absorption spectrum; if you switch to a different lighting spectrum, you can have a shift in clades as one is no longer being favoured over the other. This transition period might cause issues as there is a change over between the dominant algaes (ie. dominant food source).

If you are seeing basal STN, that signals to me starvation which makes me think the above. Try turning down the lights a little bit and feed a bit more. Try amino acids if you haven't already; I have found them to be particularly good at fighting STN.

[Bblinks]

Originally Posted by ScubaSteve

Ok, this is just my opinion here, so take it with a grain of salt...

ULNS keep corals "trim and fit" to keep those nice colours, meaning they have little "fat" (aka excess zooxanthellae) to help them ride out system disturbances. With ULNS, we are essentially keeping them on the knife's edge. This is why so many people in the beginning of biopellets were having recession problems: the corals were starving.

The dramatic change in lighting conditions (not just intensity, but spectrum) probably caused the SPS to freak out a little while adjusting. You didn't spike the lighting, so it's not shock, but being at the intensity you are now they might not have enough zooxanthellae or pigmentation to handle the increased photons rates. This can cause photoinhibition (meaning too much light is causing them to shut down) or they're heating up at the skeletons due to the lack of skin pigmentation (ie. coral sunscreen). This can (and does) happen when you swap to new bulbs, new fixtures, etc. The change in intensity from T5 to LED is probably what triggered it. Corals that aren't pushed to the limit by ULNS can usually ride this out without ill effect.

Also, a shift in spectrum (LEDs are narrow spectrum compared to halides and T5) can cause a shift in which zooxanthellae clade is dominant in the coral. Each clade has it's own specific absorption spectrum; if you switch to a different lighting spectrum, you can have a shift in clades as one is no longer being favoured over the other. This transition period might cause issues as there is a change over between the dominant algaes (ie. dominant food source).

If you are seeing basal STN, that signals to me starvation which makes me think the above. Try turning down the lights a little bit and feed a bit more. Try amino acids if you haven't already; I have found them to be particularly good at fighting STN.

+1 Good call Steve. I think you hit the nail on the head.

[doch]

ScubaSteve:

You think that this would happen almost immediately after changing the lights though? (I started them out at 30%) I have been using KZ Amino Acids... but not religiously. I will try to use it daily instead of a couple of times a week. What would you suggest for 'food' for them? I dose much of the KZ line, but no phyto, or food per se. There should be some mulm coming off of the Zeo rocks though. I do have a couple of types of coral food... NLS powder and Acan plus... Acan plus is likely too big..? Maybe the NLS stuff would help?

I appreciate the write up... any opinions are gatefully accepted... I'll try anything.

[doch]

Something else that I should mention... many of the corals that I'm having problems with are towards the bottom of the tank... still lean towards the lights as the issue?

[sphelps]

Originally Posted by doch

Something else that I should mention... many of the corals that I'm having problems with are towards the bottom of the tank... still lean towards the lights as the issue?

I would say it's light related although not intensity and like I said before something else must be at play as well. Many of the SPS I lost were next to LPS corals which seemed unaffected.

As for zeovit IME it doesn't push coral health to edge, when I used it my SPS corals were much healthy and resilient than before. While some products can cause brief coral stress for long term benefit for the most part vitality was increased. I use to change halide bulbs all the time without any adverse effects on the SPS and no acclimatization was required. I even use to be able to kill off algae with controlled kalk overdoses so the corals were the furthest thing from the edge.

I think we have much to learn about the true effects of LEDs on coral, especially SPS. While many do just fine there are many of us that bleach and loose corals from LED transition and it simply can't just be intensity or spectrum as switching halides and T5s is common practice, often going to a completely different spectrum and doubling par without ill effect.