Does carbon bleach your corals ? (Kent carbon recall)

[Casey8]

I was using Kent reef carbon corals for years without any problem until 2 days ago. I did water change on Monday evening, everything was fine and normal as usual. Tuesday afternoon, I changed the carbon. I used 1 cup for 100 gallons as instruction and as I normally do, so I am sure I didn't overdose it. But Wednesday morning, woke up and looked at the tank, all my sps corals were bleached. I did 25% water change right away. Today, I did another 25% water change because the corals look even more bleached. Even the hardest coral I have for more than 3 years and has been growing to almost 10 inch is also bleached more than half way I used to buy the smallest size of Kent reef carbon, but this time I bought a 1 gallon container, and that was the first time I was using it on Tuesday. I don't think buying smaller size or bigger size is different from the quality of it. But I had turned off the carbon today, because I thought it must be from using this carbon, there is no reason for me to think anything else. Checked the water quality, everything was fine.
I had spent too much time and money on corals. If I loose all the corals this time, I think I will go with fish only tank. I have been unlucky with them
Hope anybody here can give me some clues what is happening to my corals.

[daniella3d]

Same here...kent carbon...most coral are pale and some bleached. All my photosynthetic sponges are dead! My pink digitata is nearly white and show no polyp extension. Polyp extension is very low even on my shaggy acropora which is not shaggy anylonger. I put Kent carbon, go to sleep and wake up to that mess.

Never again will I use that crap. What's in it that could cause this? I used all sort of brand of carbon before without any visible effect...ever.

I removed the carbon and did 2 30% water change but it might take many water change to stop the bleaching. Now things have seem to stabilize but it will take months for some of the coral to recover, if they ever do. My blue haliclona photosynthetic sponges are gone. had them for 2 years

Originally Posted by Casey8

I was using Kent reef carbon corals for years without any problem until 2 days ago. I did water change on Monday evening, everything was fine and normal as usual. Tuesday afternoon, I changed the carbon. I used 1 cup for 100 gallons as instruction and as I normally do, so I am sure I didn't overdose it. But Wednesday morning, woke up and looked at the tank, all my sps corals were bleached. I did 25% water change right away. Today, I did another 25% water change because the corals look even more bleached. Even the hardest coral I have for more than 3 years and has been growing to almost 10 inch is also bleached more than half way I used to buy the smallest size of Kent reef carbon, but this time I bought a 1 gallon container, and that was the first time I was using it on Tuesday. I don't think buying smaller size or bigger size is different from the quality of it. But I had turned off the carbon today, because I thought it must be from using this carbon, there is no reason for me to think anything else. Checked the water quality, everything was fine.
I had spent too much time and money on corals. If I loose all the corals this time, I think I will go with fish only tank. I have been unlucky with them
Hope anybody here can give me some clues what is happening to my corals.

[Lampshade]

A lot of the time the coral bleaching is from your water getting much more clear, allowing a big change in light intensity on your coral. It is very odd that it's kent though, would explain some issue's I've had recently with the same stuff. Bleaching tips on some coral like milli's, but lots of others are fine.

[daniella3d]

Not in my case. a few months ago I did 2 side by side water change 25% and no coral bleached, everything was beautiful and healthy. I had to get the nitrates lower due to a large foxface (sold) polluting my tank.

Beside, if you put the carbon in the evening and in the morning you wake up to this mess...can't be the light because it is closed at night.

It is obvious it was the carbon in my case...nothing else was added or hapened. Beside...my blue sponges died! what can kill a blue sponge??? surely not the clarity of the water. I have put chemiclean often during the past 2 years and the water become crystal clear, and that never affected my sponges nor any of my corals. Something nasty in that kent stuff...

BTW, I too bought the large container. Can there be something not right in there?

Originally Posted by Lampshade

A lot of the time the coral bleaching is from your water getting much more clear, allowing a big change in light intensity on your coral. It is very odd that it's kent though, would explain some issue's I've had recently with the same stuff. Bleaching tips on some coral like milli's, but lots of others are fine.

[Casey8]

Originally Posted by daniella3d

Same here...kent carbon...most coral are pale and some bleached. All my photosynthetic sponges are dead! My pink digitata is nearly white and show no polyp extension. Polyp extension is very low even on my shaggy acropora which is not shaggy anylonger. I put Kent carbon, go to sleep and wake up to that mess.

Never again will I use that crap. What's in it that could cause this? I used all sort of brand of carbon before without any visible effect...ever.

I removed the carbon and did 2 30% water change but it might take many water change to stop the bleaching. Now things have seem to stabilize but it will take months for some of the coral to recover, if they ever do. My blue haliclona photosynthetic sponges are gone. had them for 2 years

Thanks for your input, Daniel. I just got a new brand Marineland carbon. I had used this brand since I first started in this hobby. Now all I am hoping is I can save some of the corals left. All my favorite corals are bleached out so badly, they completely turned white today. The ones that I don't care very much are still having some faded color on them Life is like that, always lost something that you cared about and loved the most, same thing happened with fish too.

[daniella3d]

Good luck with your system. It has been about a week for mine and it is still acting wierd. I now have some brown stuff covering some corals so I am guessing some of my digitata died as well.

It would be important to find out what is causing this and if any others have had similar reaction. I did not even talk about it at first because I was a bit skeptical about carbon causing this but now that you talk about your own experience with it, then it makes me beleive that my thoughts that it was the carbon were right.

Originally Posted by Casey8

Thanks for your input, Daniel. I just got a new brand Marineland carbon. I had used this brand since I first started in this hobby. Now all I am hoping is I can save some of the corals left. All my favorite corals are bleached out so badly, they completely turned white today. The ones that I don't care very much are still having some faded color on them Life is like that, always lost something that you cared about and loved the most, same thing happened with fish too.

[Casey8]

I am glad you had chimed in that you had the same problem with this Kent carbon too. If not, I may have thought I am the only one complaining about bleaching corals for using bad carbon. Nothing I can do about coral's bleaching now, I just hope whatever I have left are recovering soon.

[daniella3d]

I once had a shaggy acropora bleach completely and no polyp extension after I took it from one tank to the other without any acclimatation. I did not care about it because under T5 it was all brown and really ugly. It remained for about a month like that and after a month the polyps started to come out and that coral is gorgious today. It has grown about 10 times the size. It took about 2 months to color up to a very nice bleu/green with purple tips under metal halide.

So there is hope

I will return that carbon to the store for a refound and tell them what hapened and that I am not the only one and will take the Seachem carbon instead.

Originally Posted by Casey8

I am glad you had chimed in that you had the same problem with this Kent carbon too. If not, I may have thought I am the only one complaining about bleaching corals for using bad carbon. Nothing I can do about coral's bleaching now, I just hope whatever I have left are recovering soon.

[Palmer]

Originally Posted by Lampshade

A lot of the time the coral bleaching is from your water getting much more clear, allowing a big change in light intensity on your coral. It is very odd that it's kent though, would explain some issue's I've had recently with the same stuff. Bleaching tips on some coral like milli's, but lots of others are fine.

That's very interesting I have never heard that before. I would wonder if there is anyway to show this via PAR readings or some other way to test light penetration into the water pre and post water treatment.

[paddyob]

I used Kent for years and years. Mo bleaching. Ever.

Temperature and too much light are usual suspects.

Highly doubt it's the carbon.


Bleaching is usually human error in tanks.