Can low calcium cause bleaching?

[Kaiser]

I woke up this morning to one of my acropora completely bleached, a montipora undata frag was half bleached, and my jf high strung acro had a small chunk bleached, so I did a 5g water change (all I had on hand, it's probably about 40g total system volume) and left (I had to be somewhere), when I came back the rest of my Monti was toasted and even more of my jf high strung was bleached so I checked my parameters, the only thing that seemed to be off was my calcium was 350, so I dosed a bit of calcium to try and raise it 20 points since the instructions say to not increase it more than 20 points per day. I did dose Triton iodine yesterday per my recommended daily dose, I don't know if that could have done something. The odd thing is I still have excellent polyp extension on everything in the tank, including the pieces that were bleaching. I'm not sure what is happening.

 

[Rakie]

If your calcium is that low I would check two things..

1. Salinity. Calibrate your refractometer, and make sure your salinity is on point.
2. Magnesium. Low magnesium means unstable calcium.

Having low salinity can mean unstable/low magnesium/calcium.

 

[Kaiser]

If your calcium is that low I would check two things..

1. Salinity. Calibrate your refractometer, and make sure your salinity is on point.
2. Magnesium. Low magnesium means unstable calcium.

Having low salinity can mean unstable/low magnesium/calcium.

Salinity is 1.025, I'm calibrating with reference solution, although I'm not sure if the solution can go bad since it is a bit old.
Magnesium is 1380, I brought it up from 1245 over the last 3 days.

 

[Rakie]

So going from 1245 to 1380 mag in 3 days is could be what caused your problem. That's an astoundingly fast and HUGE change for corals. You should be increasing like 50 per week.

Calibration fluid can be bad straight from the factory so anything is possible. Okay, so mag was low too. That will cause an imbalance. The more mag, the more calcium is available to the corals. I don't know the exact numbers, so for an example I'm totally making up on the spot, with only 1200 mag, you only had say, 300 cal available for corals. Very low.

An imbalance will cause further imbalance (kind of a DUH statement).

I would consider doing some water changes to balance things in general. If you have a large tank slow down how you dose dramatically, because big changes = death to corals.

 

[vanpire]

I woke up this morning to one of my acropora completely bleached, a montipora undata frag was half bleached, and my jf high strung acro had a small chunk bleached, so I did a 5g water change (all I had on hand, it's probably about 40g total system volume) and left (I had to be somewhere), when I came back the rest of my Monti was toasted and even more of my jf high strung was bleached so I checked my parameters, the only thing that seemed to be off was my calcium was 350, so I dosed a bit of calcium to try and raise it 20 points since the instructions say to not increase it more than 20 points per day. I did dose Triton iodine yesterday per my recommended daily dose, I don't know if that could have done something. The odd thing is I still have excellent polyp extension on everything in the tank, including the pieces that were bleaching. I'm not sure what is happening.

I sometimes have Ca @350 without any issues.

 

[Kaiser]

So going from 1245 to 1380 mag in 3 days is could be what caused your problem. That's an astoundingly fast and HUGE change for corals. You should be increasing like 50 per week.

Calibration fluid can be bad straight from the factory so anything is possible. Okay, so mag was low too. That will cause an imbalance. The more mag, the more calcium is available to the corals. I don't know the exact numbers, so for an example I'm totally making up on the spot, with only 1200 mag, you only had say, 300 cal available for corals. Very low.

An imbalance will cause further imbalance (kind of a DUH statement).

I would consider doing some water changes to balance things in general. If you have a large tank slow down how you dose dramatically, because big changes = death to corals.

Ok, I figure I can do a larger water change tomorrow to balance things out, in the meantime I hope I don't have any more losses. I don't know if it can wait but if I have to, I have some brand new water I just mixed today to fill up my 160 gallon, I would prefer to pick some up at the store and do my water change after work though.

 

[reeftivo]

Ok, I figure I can do a larger water change tomorrow to balance things out, in the meantime I hope I don't have any more losses. I don't know if it can wait but if I have to, I have some brand new water I just mixed today to fill up my 160 gallon, I would prefer to pick some up at the store and do my water change after work though.

When you say "pick some up at the store" are you referring to premixed LFS salt water? Do you use RO water to mix at home (not tap)?

 

[Kaiser]

I work at a LFS, currently I'm using my RO unit to fill my 160g, I was gonna use water I get from work to do the water change but I woke up this morning to an entirely bleached JF High Strung so I took about 10 gallons out of my fresh batch and did the water change this morning. Wish I had caught it sooner, my high strung was doing really well prior to this [emoji20]

 

[reeftivo]

only time i've had fast bleaching and tissue loss was when i had a CO2 dump from an empty ca rx tank. it raised my alk through the roof. I was running pretty low nutrients (3ppm no3,0.2 ppm po4).

what's your alk at? sorry, i didn't see it posted

 

[Kaiser]

only time i've had fast bleaching and tissue loss was when i had a CO2 dump from an empty ca rx tank. it raised my alk through the roof. I was running pretty low nutrients (3ppm no3,0.2 ppm po4).

what's your alk at? sorry, i didn't see it posted

Alk is 7.7, running ulns and I've been trying to get a detectible nitrate for a long while, but this happened suddenly so I don't think it was because I zero'd out. I lost my exquisita Stag this afternoon, did another 10 gallon water change, I'm a bit worried here.

Salinity: 1.025
Alk: 7.7
Ca: 350 (before dose)
Magnesium - 1380
Phosphate: 0
Nitrate: 0

 

[Randy Holmes-Farley Verified Community Expert]

I think it unlikely either the calcium at 350 or the mag boost bleached corals, unless it was a poor grade of magnesium with substantial impurities.

 

[Kaiser]

I think it unlikely either the calcium at 350 or the mag boost bleached corals, unless it was a poor grade of magnesium with substantial impurities.

I was using esv magnesium since it was the only mag supplement I had on hand. It seemed almost like a film that covered the bleached sps. It also seemed to spread on contact as the frags on my rack were the ones affected, and the ones closest to the affected frags would be the next to bleach. it affected acropora and montipora as well. It's gone away now as far as I can tell but it was really strange. Once it started I kicked up the water changes to 25% a day. Lost a few of my favorite pieces [emoji22].

 

[Graffiti Spot]

I agree with randy. Were the corals that bleached growing well before hand or were they not really doing anything? Pictures of the corals in the tank might help here, there is not much to go on. I would buy some new refractometer calibration solution since it will start to give different results over time if not in a good bottle and stored well, just my experience. Some refractometers are junk too, which one do you have?
It sounds like a bacterial infection and rtn, or is it actually bleaching? There is a difference. Bleaching is the corals not dying but going white and still having its flesh and polyps, but that doesn't normally happen from coral to coral it normally happens all at once.

 

[Kaiser]

I agree with randy. Were the corals that bleached growing well before hand or were they not really doing anything? Pictures of the corals in the tank might help here, there is not much to go on. I would buy some new refractometer calibration solution since it will start to give different results over time if not in a good bottle and stored well, just my experience. Some refractometers are junk too, which one do you have?
It sounds like a bacterial infection and rtn, or is it actually bleaching? There is a difference. Bleaching is the corals not dying but going white and still having its flesh and polyps, but that doesn't normally happen from coral to coral it normally happens all at once.

It seems to have been bacterial, the corals would just die and not leave anything behind, even polyps. The corals were all growing really well beforehand, which contributed to the issue since they were covering the rack and were in closer proximity to each other, making transmission easier.