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Button Polyp Bleaching

3K views 11 replies 2 participants last post by  PrairieReef 
#1 ·
Hi guys, recently i purchased a 3 gallon nano aquarium that I intended to convert to a reef only tank. I set it up with live sand, live rock and added marine bacteria about a week and a half ago. i bought my first frag today and about 3 hours after putting it in, it started secreting brown "threads" which i researched to discover coral bleaching was taking place. How an i stop this?

Salinity: 1.020 Temp: 26 C

not sure how powerful the lights are but i would say very.
 
#2 ·
What are the lights? Depending on the lights, there may be a variety of ways to diffuse them and/or move the coral.

How did you acclimate? That salinity is pretty low for corals I think. More typical is 1.024
 
#5 ·
I assume at that wattage you have LEDs?

Then I would suggest moving them clear to a corner way from the light. LED's focus pretty much straight down (most often) so just moving a coral a little off center can have a huge decrease in intensity.

The other option is to use some screening over the tank in that spot to shade it.

Your acclimation should have been fine for polyps, but again, the salinity is a little low for corals - perhaps too low. Any kind of distress can cause them to expel.

I assume you've tested for ammonia and nitrites?
 
#8 ·
yes - too much light is a major cause of bleaching. The zooxanthellae over produce in the coral and the coral will expel them to protect themselves. Generally PAR values for button polyps would be in the range of 50-100 PAR. Maximum I would suggest would be around 400 par. Anything higher than 700 PAR is too much for any coral and you will start to see bleaching. You can:

Reduce the photoperiod - most people are around 8 hours.
Reduce the intensity by raising the lights
Reduce the intensity by adding a screen
Use a dimmer to reduce intensity.

If they are LED's I would either ra
 
#10 ·
That's the kicker - PAR meters run $350 plus and don't measure the very discrete wavelength bands of LEDs well anyway. What most people do is go by the manufacturer measures - they typically list these for most well known lights. Places like advancedaquarist.com sometimes also do reviews where they list the PAR values.

With LED's being relatively new this information can be hard to find.

I'm lazy I guess - that is why I went with lights that actually provided graphs of PAR at various depths of tanks given a distance hung above the water line over a specific square inch area. I knew what I was getting. I paid more for the lights - but that information was part of what I was paying for.

Otherwise - you can just raise and lower them till you seem to hit a sweet spot that everybody appreciates. You can then slowly lower them as corals get used to the light, but there is a limit to what they can handle. Of course the higher the light, the more coverage but the less PAR. The lower the light, the less coverage, but the more PAR - meaning you may need to get two lights to cover the tank if you hang them low. If you don't need that intensity, you can use fewer lights hung higher to get better coverage.

Or you can check with local reef clubs to see if they will rent or loan their par meter. Often they will only loan PAR meters to members.
 
#12 ·
:D NP! Just giving back to the community that helped me so much when I was starting. Still have ton's to learn myself!
 
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