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Acropora Bleaching

post #1 of 18
Thread Starter 
I have several acropora's and one of them is bleaching. I have it high in the tank under blue line metal halides and I feed DT's and Marine Snow. Is there anything that can be done to keep these type of corals from bleaching? Why are the acropora so hard to keep?

post #2 of 18
Thread Starter 

I have had the Acropora several months. The reason it is on top is because that is where I was told to put it for more light when I bought it. I've always had it on the top. Is it possible that the blueline metal halide is not strong enough for it? Since it has started bleaching, will it continue to bleach and then die? Is there anything I can do to stop the bleaching?

The temps in the tank have remained the same.

post #3 of 18
Acropora is not hard to keep, but they do require the proper conditions, ie fast current, strong lighting, godd water quality and elevated Ca and alkalinity levels. Has anything changed in the tank lately, has it been knocked over? Is it bleaching from the tips, or from the bottom. What color is it? What wattage are you MH? The first thing I do when a coral appears unhappy is move it to another spot. HTH
post #4 of 18
Lets get the facts first:

MH wattage and kelvin temp.?
Wild or propogated Acro?
Water parameters?
Acropora type and color?
Light in the tank it was purchased from?
How long have you had it?
How often do you add Marinesnow and DT's to the tank?
How many SPS corals are in the tank?
How big is your tank?
Whar other corals are in the tank also?

post #5 of 18
Thread Starter 

The 3 metal halides are 175W, two metal halides are the blueline bulb and one is a 50/50. The Acro's are proprogated, the water perimeters are salinity 1.025, calcium 450, iodine 0.6, phosphate 0, nitrate 0.5, alkalinity is 5.50. I don't know what type of lights the Acro's where under before I got them as I bought them from FFish. I have had them about 3 months and one of them is bleaching from the bottom. I use Marine Snow about every other day. My tank is 75 gallon and has the following: torch, brain, leathers, xenia, anthelia, mushrooms, polyps, frogspawn, pipe organ, long tentical plate, pagoda's, gonipora, colt.

It was suggested to me from FFish that I was not leaving my lights on long enough. I have one blue spectrum to come on at 9 and cut off at 12 and then the other two come on at 12 and cut off at 5 and then one blue comes back on at 5 and cuts off at 8. They also said that my salinity was too low so I raised it to 1.025.

Hope this helps! :)
post #6 of 18
I had the same problem once. My Acopora started to bleach from the bottom up. The way that I fixed the problem was I simply moved it to another location. If the bottom to the coal doesn't get enough light it will set off a chain reaction and you may end up loosing the entire coral. Try to set it directly under the MH 50/50 and see if it recovers. You will have to keep a close eye on it because bleaching can take place very rapidly. After I moved mine (only 6'') it turned from brown (how I bought it) to green. Best of luck.
post #7 of 18
The information about the bulbs was incomplete, I need the Kelvin(K) rating.

What type of Acro is bleaching and its color?

175watt is low for most Acroporas, ff probably had them under 400watt MH lights.

post #8 of 18
Thread Starter 

The bulbs are 175W 12K and the acropora is brown in color and is of the Cerealis species. I do not have any daylight bulbs or the the 175W 50/50.

post #9 of 18
Thread Starter 

The Acro that is bleaching was on top of the aquarium under a metal halide so I don't know if that was the problem or not. I may have to remove one of the 12K blue and replace it with a daylight bulb but don't know what Kelvin I should use if I have to do this.

Thanks for your reply!
post #10 of 18
Donna, I think that BurnNSpy is right about not having enough light. I also have 12K MH lighting except I use 400w bulbs. I have the coral 3/4 high in the tank directly under the light. If I could speculate, I would say that your coral shouldn't be brown, it should be green under the right lighting conditions. Mine was brown when I bought it but after I fed it the 400w ball of fire it turned green and is now thriving. If you do go to a daylight bulb may I suggest 6500k and S.O. blue actinic on the side. But as far as your concern, I don't think that having it under the light was the problem.
post #11 of 18
Thread Starter 
Deep Blue

I have a 65K bulb but what are you talking about using a blue actinic on the side? Are you talking about a strip light using the blue actinic bulb? I had a double strip across the back of the aquarium and I took it off and added another 175W metal halide. Should I go back to the strip and eliminate the metal halide that hangs over the back of the aquarium and then use one 6500K light and one blueline bulb across the front?

post #12 of 18
Is this coral bleaching or is it receding?? They look nearly the same but are for very different reasons.

Did you just raise the salinity and time on the light? or did you do that before he coral was in the tank?

post #13 of 18
Thread Starter 

I raised the PH yesterday and I have not changed anything on the lighting yet. The Acropora was already bleaching before I changed the salinity. I am waiting on someone to tell me if I need to change my lighting. It was suggested that I add a daylight bulb (6500K) and add a actinic but I would have to remove the metal halide that is positioned over the back of the tank in order to add a strip light for the actinic.
I have not changed the time of leaving the lights on yet. Do the metal halides need to be on 12 hours? Back when I bought the metal halides, I was told to only leave them on 5 hours and then the blue 12K bulb comes on until 8PM. Lights are on from 9 AM to 8 PM.


[ June 28, 2001: Message edited by: donna2933 ]
post #14 of 18
Try having all the bulbs on to boost the wattage
post #15 of 18
Your lighting is confusing and I don't think you understand what our answers mean.

I think you have 3-175watt 12000K MH bulbs.

If so then they need to be placed evenly across the top of the tank.

If you have two strip lights, then I suggest adding them to the hood one on the front edge and on on the back edge of the hood with the MH bulbs between them.

Assuming the 3-MH bulbs are 12000K, I would use 2 50/50 VHO strip bulbs.

Your lighting is too weak for most Acros and you should consider getting 1-250watt 10000K or 12000K MH setup to replace 1-175watt, then place the Acros under that bulb. The Acros are usually brown when not getting enough light.

I hope I cleared things up.

post #16 of 18
Thread Starter 

Sorry it took me so long to get back to you. I have had computer problems and haven't been on line lately.

I have 3 175W 12K metal halides. One of them is positioned over the back of the tank the other two are positioned across the front. I have a double strip light( both strips in one fixture)but haven't been using it until just recently and I can't use the metal halide on the back because that is where the strip is.The strip light has 1 actinic and 1 20K bulbs.

From what you are saying I will need to get a higher wattage metal halide fixture and do away with one of the 175W if I am going to keep acropora. I don't know if the pendant balast I have now would support a higher wattage bulbs than the 175W so would porbably have to buy another.

Thanks for you information.

post #17 of 18
You may want to consider the age of your current bulbs as well. Might they just need replaced?

Also Acropora cerealis typically are pale brown and cream in their natural enviornment So for most, 175 watt MH is enough for this particular species IMHO. Some have pink green or purple tips......some, not most.

post #18 of 18
Thread Starter 
The bulbs are only 3 months old. So far I haven't had any others to loose their color.

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