Help. Nitrate swing Causing Hammer coral to Bleach

[SoftieReefer]

I have a 40-gallon reef tank and recently performed a large water change that caused a significant nitrate swing. Since then, several of my corals have started declining and appear to be dying.

Is there anything I can do to help stabilize the tank and save the remaining corals?

Sorry for the blue-light photos.

Parameters Before Water Change:

• Phosphate: 0.66 ppm
• Nitrate: 13.12 ppm

Parameters After Water Change:

• Phosphate: 0.55 ppm
• Nitrate: 2.7 ppm

 

[Randy Holmes-Farley Verified Community Expert]

how large was the water change? I would not assume nitrate is the primary issue.

 

[SoftieReefer]

how large was the water change? I would not assume nitrate is the primary issue.

It was about 10 gallons.

 

[Mr. Mojo Rising]

I very regularly do 50%+ water changes, I've even done 80% water changes, I've done 30% water changes daily for a week, I never had any issue and will never believe that water changes bother corals. As long as you match the temp and salinity (and not change the alk too much) it should be fine, and even if you did not match it but were close enough it would still probably be fine. Something else is amiss here.

Can you post some pics, including a full tank pic, in white light?

 

[SoftieReefer]

Here are some white light photos

 

[Peer.Boerner]

@Mr. Mojo Rising makes an excellent point. Could your water be the issue? Maybe too hot or cold or a salt change or perhaps a toxin of some kind? Do you make your own water or buy from a store? Hope you figure it out!

 

[SoftieReefer]

I make my own Rodi water. I checked the salinity and temp before doing the water change. I just changed my RODI filters a month ago. What can I do to check if there are toxins? Is it possible to save the hammer corals?

 

[Mr. Mojo Rising]

None of the corals are thriving except the ricordias and the gsp at the top. What kind of light do you have? There is a lot of shadowing I wonder if the lights are too low.

 

[SoftieReefer]

AI Prime Hd 12in Flex arm.

 

[Mr. Mojo Rising]

I’m sorry but I think that the problem. I have a 150 watt light on my 40 gallon, AI Prime is only 55 watts and kind of like a spotlight, it doesn’t have good spread. I have AI Prime on my 15 gallon set at 85%. Get yourself a Nicrew 150 watts and then watch your corals grow. Good luck.

 

[SoftieReefer]

The coral started turning white immediately after the water change, but they began opening up within a day of being placed back in the tank. I had them for about 2 weeks. Could it be something other than the nitrate swing?

 

[Randy Holmes-Farley Verified Community Expert]

It was about 10 gallons.

Ok, but I either need to know the percent change or the tank size to know what sort of effects one expects.

 

[SoftieReefer]

Ok, but I either need to know the percent change or the tank size to know what sort of effects one expects.

40 gal. tank, 10 gal. water change

 

[Peer.Boerner]

@Mr. Mojo Rising makes an excellent point. Could your water be the issue? Maybe too hot or cold or a salt change or perhaps a toxin of some kind? Do you make your own water or buy from a store? Hope you figure it out!

Not sure how to measure toxins but there may be little harm in adding activated carbon to your filtration just to absorb anything problematic. I’ll defer to others regarding light intensity but that too can be an issue, but problems right after a water change leads me to think more about a chemistry problem. Keep us posted. Best of luck!

 

[Randy Holmes-Farley Verified Community Expert]

40 gal. tank, 10 gal. water change

The nitrate drop is not too large from such a change, and the change in nitrate you report would not be that large from the water change. Probably some test error mixed in, which is expected.

 

[Rocks reef]

I am in agreement with the replies.
@Fish Fan you have any ideas?

Randy is correct, the nitrate drop isn't an issue and the water change is not what caused the issue. I've done almost 100% water changes on a 40B a few times with no issues or losses. Three of the four LPS on the rack look as if they have had complete polyp bailout. This means, the issue has been ongoing for quite some time and the water change may have been the straw that broke the camels back.

Mojo hit on an important factor. Light. As he mentioned, the AI HD has quite a small spread and is underpowered for a 40. I could see if you had two of them over it and maxed them out. The 16 HD has a maximum spread of 24x24, however, that does not mean there is sufficient PAR in that 24x24 area. In actual use, you are looking at closer to an 18x18 area, even then the outer edges won't have much PAR. It is rated at approximately 100 PAR at 24" deep, however, this is DIRECTLY under the light. I feel the corals have been struggling, stressed and slowly bleaching for a while as there hasn't been enough PAR to feed the zooxanthellae. Essentially starving the corals over time.

Please don't take this as criticism. I'm hopefully explaining it in a way that makes sense.

 

[SoftieReefer]

I am in agreement with the replies.
@Fish Fan you have any ideas?

Randy is correct, the nitrate drop isn't an issue and the water change is not what caused the issue. I've done almost 100% water changes on a 40B a few times with no issues or losses. Three of the four LPS on the rack look as if they have had complete polyp bailout. This means, the issue has been ongoing for quite some time and the water change may have been the straw that broke the camels back.

Mojo hit on an important factor. Light. As he mentioned, the AI HD has quite a small spread and is underpowered for a 40. I could see if you had two of them over it and maxed them out. The 16 HD has a maximum spread of 24x24, however, that does not mean there is sufficient PAR in that 24x24 area. In actual use, you are looking at closer to an 18x18 area, even then the outer edges won't have much PAR. It is rated at approximately 100 PAR at 24" deep, however, this is DIRECTLY under the light. I feel the corals have been struggling, stressed and slowly bleaching for a while as there hasn't been enough PAR to feed the zooxanthellae. Essentially starving the corals over time.

Please don't take this as criticism. I'm hopefully explaining it in a way that makes sense.

 

[Fish Fan]

I'm following, but I like to let Randy address the chem questions in his sub-forum

I do agree, I do large 80%+ water changes with no ill effects, you just need to match temp, salinity, and ideally alk. I think there's another water quality issue, or lack of light or poor flow going on.

 

[SoftieReefer]

Here are some update photos. I did remove a lot of zoanthids before the water change. Some of my corals look completely fine. Is it too late to save the others? Should I do another water change? In picture 2 that rock used to be completely covered in zoanthids before I removed them.