Burnt tips but why...

Reefer40b · Sep 29, 2018

just a little up date,Things seemed to have halted now with my Alk running at 7.7, need to do more water changes just need the time for it... Pink millie RTN but I snagged a frag before it went up in smoke so I still got her with me! What really surprising is my red dragon has lost half its tissue but has stopped. This coral has been through a lot lately just two weeks ago fish knocked it off while I was at work and came home to it sitting on my acan colony covered in mucus, re-mount thinking it was surely a goner(all tissue under the coral died but thats all fast forward two weeks to now, recently with the burnt tips issue it rtn halfway and stopped and still isn't dead! The only coral I lost from this was my gonzo cotton candy, which is a real bummer as I don't know anyone else who has it...

Makers Marc · Nov 7, 2018

jda said:
You can burn tips from bad LED light... usually turned up too high.

When people say low alk, they mean 6 to 7. I would still consider 8.X to be too high if your building blocks were indeed too low, but I do not think that they are. 10n and .2p is plenty growth limiting enough to impede calcification. In any case, you might want to aim more to the 7.0 level if your disposition is to keep it safe.

You can get burnt tips with too much direct flow - the water peels the tissue right off.

Fish that get a taste for acropora flesh can cause damage too.

Do you have any photos?

LED Hotspots definitely.

MARK M. DAVIS · Nov 8, 2018

Higher lighting exacerbates burn tips due to the photosynthesis process production of excess o2 that irritates the coral whereby, they expel the zooxanthellae for survival. If things don't change, or excess o2 not exported, the coral will bleach and die.

jda · Nov 8, 2018

The problem with burnt tips from LEDs does not appear to be from higher quantity - most of these corals will do fine with higher quantity of other types of light. Nobody knows why, but it appears to be a quality issue.

For example, Radion in my friend's tank will burn the tips of his acropora at about 400 PAR, but they will thrive under 800 PAR in my frag tank under MH. He keeps them at 350, which is enough, to keep this from happening.

Makers Marc · Nov 13, 2018

jda said:
The problem with burnt tips from LEDs does not appear to be from higher quantity - most of these corals will do fine with higher quantity of other types of light. Nobody knows why, but it appears to be a quality issue.

For example, Radion in my friend's tank will burn the tips of his acropora at about 400 PAR, but they will thrive under 800 PAR in my frag tank under MH. He keeps them at 350, which is enough, to keep this from happening.

I agree it is probably not from a Par measurement perspective. But unsure if "quality" is necessary the right term, unless someone tells me Kessil AP700s aren't.

jda · Nov 13, 2018

This is going to open a can or worms, but I think that Kessil is a quality LED, but still nowhere near the quality spectrum of a Mercury based bulb... there is no IR or UV to start. IR can stimulate energy transfer between PSII and PSI and make it easier for the coral to use energy. This is not in the spectrum visible to the human eye and will not show up on a PAR meter, so some LED manufacturers leave it out since it does not sell units and takes a deeper understanding than just looking at a PAR chart. This is not just a Kessil thing... it happens with lots of other units. There is some reason that LEDs have a ceiling below what you can accomplish with a T5, VHO, PC or Halide... nobody has the full answer, unfortunately.