Bleaching after a water change?

[ecotoxlady]

Hey guys! Been a while since I posted on here but lab work has been keeping me busy. I apologize if someone else has already asked about something similar. I did a large water change over the weekend and literally ALL of my SPS aside from one acro and one millipora have bleached. I really don't understand this. I can say that I recently changed my MH bulb as the old bulb was well...old (about 9 months) and I did notice when I did the water change that some of my SPS looked a bit fainter in their coloration and stressed so I suppose this may have been inevitable but I would think that clean water would help the situation, not hurt it. Have any of you ever experienced this phenomenon? I have cut back the lighting on the tank from 8 hours to 4 hours just to be safe. Also, what are the chances that any of my SPS will recover? I had some beautiful large montipora plates in my tank that would be devastating to lose completely. Any opinions would be greatly appreciated as well as any advice to try to save these SPS (I still do see some polyps extended but they are completely devoid of color).

 

[gilmour01]

i've had bleached sps come back

 

[ecotoxlady]

Was there anything in particular you did to help it along?

 

[gilmour01]

just made sure my params were in order

 

[Sikryd]

Not much you can do now, except wait.

My guess would be that your PO4 was high, and with the large water change it went down real quick, which can cause bleaching

That or your Alk was low and went high with the change.

 

[Murfman]

What was your tank temp vs the water change temp?

 

[ecotoxlady]

There definitely was a difference in the water temp of the new water but I was a bit lazy with this water change since I used premixed store bought water. My water was around 77 degrees (digital thermometer) before the water change and after the water change, it dropped to around 71-72. I'm sure this didn't help things but I'm now primarily focused on what I can do to nurse my SPS back to health. I did leave out the fact that part of my urgency in doing this water change was that we had had 2 consecutive days of rather long power outages due to severe thunderstorms (8 hours in one case) which a day later resulted in the demise of one of my beloved clownfish. I was afraid his death could cause the loss of my corals so I wanted to act quickly to clean up the tank this last weekend.

 

[stunreefer]

Did you shorten photoperiod after adding new bulb, or only after this experience?

Did you test params of the fresh-mixed SW?

Did you leave the MHs on while performing the water change?

FWIW, corals can handle temp swings, but we're generally talking 2-3 degrees (F) over a 24 hour period. 5-6 degress in minutes will stress them out pretty bad.

Go slow, and let everything come back in line, if they're still alive and just bleached they should be fine.

 

[Sikryd]

There definitely was a difference in the water temp of the new water but I was a bit lazy with this water change since I used premixed store bought water. My water was around 77 degrees (digital thermometer) before the water change and after the water change, it dropped to around 71-72. I'm sure this didn't help things but I'm now primarily focused on what I can do to nurse my SPS back to health. I did leave out the fact that part of my urgency in doing this water change was that we had had 2 consecutive days of rather long power outages due to severe thunderstorms (8 hours in one case) which a day later resulted in the demise of one of my beloved clownfish. I was afraid his death could cause the loss of my corals so I wanted to act quickly to clean up the tank this last weekend.

The bleaching was caused by the lack of O2 - same as for the clown.

No biggie though - they should hopefully bounce back in ~a month. It usually just takes some time and stable parameters.

 

[ecotoxlady]

Did you shorten photoperiod after adding new bulb, or only after this experience?

Did you test params of the fresh-mixed SW?

Did you leave the MHs on while performing the water change?

FWIW, corals can handle temp swings, but we're generally talking 2-3 degrees (F) over a 24 hour period. 5-6 degress in minutes will stress them out pretty bad.

Go slow, and let everything come back in line, if they're still alive and just bleached they should be fine.

I'm embarrassed to admit that no, I didn't shorten the photoperiod after adding the new bulb but I had figured since it was the same bulb make and kelvin that other than the burn in period, it wouldn't be too much of a difference (I definitely should've known better).

I didn't test the params of the fresh-mixed SW but I have bought this pre-mixed SW before with good results every time I have used it and since I had a sense of urgency to get the water changed and the pre-mixed water is sold in 5 gallon units, I didn't have the patience to test 6 units.

I have added this pre-mixed salt water to my tank before at similar temps and not had ill effects so I really thought it would be alright but probably the combination of stressors including the temperature drop didn't help.

They are at this point definitely still alive (I can still see polyps) so I will do my best to keep them happy and hopefully they will recover.