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Old 01/11/2008, 07:45 AM   #1
damura
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Phosphate/Nitrate levels in relation to bleaching

Hi all,

I was wondering from your experience or from an article on the web, what are the relations between these 2 parameters to SPS bleaching. Lately i have noticed Cyano bacteria together with SPS sporadic bleaching os my SPS's. Obviously the levels of my nutrients have gone up.
My question is:
From what levels am i suppose to see bleaching? i know that some SPS's are more valnurable than others. I just want to get the order of magnitude, e.g. is it from above 0.1ppm Phosphate or, say 1ppm?
I have also noticed that my alkalinity dropped to 5.5dKh, so maybe i have fluctuations in pH. What inputs or articles can i read about these chemical parameters in relation to bleaching?

Thanks.


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Old 01/11/2008, 07:45 AM   #2
damura
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Phosphate/Nitrate levels in relation to bleaching

Hi all,

I was wondering from your experience or from an article on the web, what are the relations between these 2 parameters to SPS bleaching. Lately i have noticed Cyano bacteria together with SPS sporadic bleaching os my SPS's. Obviously the levels of my nutrients have gone up.
My question is:
From what levels am i suppose to see bleaching? i know that some SPS's are more valnurable than others. I just want to get the order of magnitude, e.g. is it from above 0.1ppm Phosphate or, say 1ppm?
I have also noticed that my alkalinity dropped to 5.5dKh, so maybe i have fluctuations in pH. What inputs or articles can i read about these chemical parameters in relation to bleaching?

Thanks.


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Old 01/11/2008, 07:45 AM   #3
damura
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Phosphate/Nitrate levels in relation to bleaching

Hi all,

I was wondering from your experience or from an article on the web, what are the relations between these 2 parameters to SPS bleaching. Lately i have noticed Cyano bacteria together with SPS sporadic bleaching os my SPS's. Obviously the levels of my nutrients have gone up.
My question is:
From what levels am i suppose to see bleaching? i know that some SPS's are more valnurable than others. I just want to get the order of magnitude, e.g. is it from above 0.1ppm Phosphate or, say 1ppm?
I have also noticed that my alkalinity dropped to 5.5dKh, so maybe i have fluctuations in pH. What inputs or articles can i read about these chemical parameters in relation to bleaching?

Thanks.


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Old 01/11/2008, 07:52 AM   #4
Randy Holmes-Farley
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I've not seen much info or commentary from the many posters here with elevated phosphate (or nitrate) that connects phosphate and bleaching. It leads to browning due to excess zoox, and to algae problems and slow hard coral growth.

Low alkalinity will certainly stress hard corals, and I would not recommend keeping it belie about 7 dKH. That said, most folks do not typically report bleaching, but rather other undesirable effects, including corals dying.

Do you know it is bleaching (expulsion of zoox) and not something different like RTN? Have any of the corals reacquired their zoox?

The effects of elevated nitrate on corals is fairly mild and not well documented, IMO.


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Old 01/11/2008, 11:32 AM   #5
CleveYank
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Re: Phosphate/Nitrate levels in relation to bleaching

Quote:
Originally posted by damura


Lately i have noticed Cyano bacteria together with SPS sporadic bleaching os my SPS's.

I have also noticed that my alkalinity dropped to 5.5dKh, so maybe i have fluctuations in pH.

Congrats damura,

Chances are good a phosphate level is not the entire worry in play I believe.
You are duplicating the experiment that some scientist believe is responsible for the conversion towards a higher oxygen content atmostphere on earth that took place a few billion years ago or so.

The bad part is how you are getting there. And what's worse is that the high phosphate with the cyano growth is leading to the major reason for your SPS decline I believe.

The major reason is that the cyano is probably trying to grow on everything in site including the surface tissues of your SPS. And if the nutrient levels via phosphate are higher than they should be then the SPS is naturally under stress. Phosphate levels are pretty much a -0- level goal for SPS is recommended to keep them from going into stress. And add higher than normal nitrate and you're in the bonus round for SPS stressing.

Since the rise and fall of food nutrient (or too high a bio-load) is causing a rise and fall of pH, and thereby a rise and fall of CO2 and a rise and fall of phosphate is interferring with your SPS to take up Ca if I'm not mistaken. It's probably not too friendly for SPS. Ionic balance is probably doing a see saw with all of this as well.

Other than rotting food/excessive waste...Cyano likes another add-on as well.
You can or may also have bulbs that are wasted and need replaced. Spectrum shift, if really far can cause problems with some/most SPS and can lead to some more stress. And since the cyno is rumored to thrive in tanks with nutrient and bulbs that are shifted. Under stress SPS would not be loving life in that kind of environment. Bleaching, RTN are more likely if prolonged condition is maintained.

Current (ie no dead spots) is also associated with cyano prevention. But if the nutrients are not there, it's usually not as much of an issue.

Is your bioload off the charts?
If you are overfeeding, work on that. If that without enough skimming, upgrade to a higher output skimmer.
If you are not compensating for above then get to 20% water changes mark and get some GFO and lower the phosphates towards -0-.
If you have PC or VHO or over driven T5's and they are 8 months or more old you may need to spring for bulbs. If you are using MH's that are over 12 to 18 months old dependent upon type and brand you may need to replace those as well.
Consider upping your clean up crew to help(smallest hermits you can find and a good source of snails).

Take what you can use and toss the rest and I hope you get it all dialed back in.


Good Luck.


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Old 01/11/2008, 01:17 PM   #6
Billybeau1
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I can't think of any articles off hand but I can tell you you should try and keep your PO4 level below .03 ppm and since you are talking sps, nitrates as low as possible.

You may post your question in the SPS forum as many folks in there have been down this road.

Also if your alkalinity is in fact 5.5 dkh then that is too low and it should be raised to at least 7 dkh. 9 may be better.


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Old 01/11/2008, 04:47 PM   #7
bertoni
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Bleaching is a fairly complicated phenomenon, and I thought it was more related to heat, lighting, and perhaps disease than phosphate and nitrate.

Phosphate begins to interfere with calcification at about 0.03 ppm:

http://www.advancedaquarist.com/issues/apr2002/chem.htm

Both phosphate and nitrate can cause coloration changes and perhaps encourage polyp bailout and other problems, as well.

Alkalinity should be maintained between 7 and 11 dKH:

http://www.reefkeeping.com/issues/2004-05/rhf/index.htm

Low alkalinity will prevent calcification and limit growth.


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Old 01/12/2008, 01:22 AM   #8
damura
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Thanks for your answers guys,

First of all, and regarding Randy's question. I was wrong indeed when calling it bleaching. It is STN, tissue necrosis that advances slowly from the base of some corals up to the stems.
I forgot to mention that i have a B.Sc in Chemistry so i know a lot about water analysis and reactions.
If i need to bet on the cause of the problem i would put it all on low Alk. i think it both causes pH swings and makes ortho phosphate more available in the water (which then feeds the Cyano).
The problem is that i do not have a pH electrode now ... I have the Hanna instrument but not the electrode (you have to replace it every 1-2 years and every such electrode costs here 100 Euros!!!)

About the alkalinity,

I was wondering how fast can it drop? I was shocked yesterday when i found that it's only 5.5 dKh!!! it was about 8.5 dKh about 2 months ago. I am measuring Alk. with Elos test kit which i'm sure that is quiet good. According to your experience, what is the steepest decline in Alk.?
I am working with Kalk reactor, but disconnected it for 2 weeks, because i suspect that the media inside it generates phosphate when it's disolving.
Could a disconnection of the Kalk reactor for 2 weeks affect the Alk. to such extent? According to my experience it definintely shouldn't!

Thanks for any answer...



Last edited by damura; 01/12/2008 at 01:54 AM.
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Old 01/12/2008, 01:29 AM   #9
Billybeau1
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Yes, alk can decline rapidly in certain tanks. I think you shutting down your kalk reactor had a lot to do with this.

A solid number is hard to give for declining alkalinity, but in your case it is certainly possible.

You could dose some baking soda to get your alk back up while waiting for your kalk reactor to go back on line.

I'm not sure why you think your reactor was adding phosphate to your tank.


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Old 01/12/2008, 01:41 AM   #10
damura
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Hi Billy,

It is a common belief, and may be a misconception among my fellow reefers that some medias, when dissolving, generate phosphate that was locked in their crystals...chemistry wise, it seems to be a logical assumption.
The question which i would really be happy to hear about is:

let's assume the media does generate phosphate when it is dissolving. But....to what extent? won't it be neglegible when comparing, for example with feedings???


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Old 01/12/2008, 01:59 AM   #11
Billybeau1
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Since I have not heard of that, I will leave this for Randy in the AM. (In our AM ). You are already in the AM I think. Heck you might be afternoon by now. Or close to it.

He is really good at this stuff and hopefully he will see this and comment.

Have a good day damura. I'm going to bed.


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Old 01/12/2008, 05:29 AM   #12
Randy Holmes-Farley
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I don't think your alkalinity got quite low enough for calcium carbonate to dissolve, unless the pH was low, either in the main tank or perhaps in specific locations like in a sand bed.

I do think the low alkalinity likely contributed by stressing the corals, then all it takes is something to push them over the edge, and most anything, including some toxins from cyano may do it. Heck, even 5.5 dKH alone might. That is really low.


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Old 01/12/2008, 09:15 AM   #13
damura
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Thanks for your answer Randy,

regarding my previous question:

let's assume the media does generate phosphate when it is dissolving. But....to what extent? won't it be neglegible when comparing, for example with feedings???

What do you think about this issue? is it really a concern?
Julian Sprung mentioned this issue in one of his books. I know that, for example, some Activated carbon medias hold phosphate and should be tested.
Should i run the same test for the kalk reactor media? i can do it by dissolving some of it in acid and then measure the solution for traces of phosphate.
As i see this issue, the question here is not qualitative it is quantitative, meaning, even if there are traces of phosphate locked in the kalk reactor media, isn't it neglegible, especially when comparing to, say, feeding?

Thanks.


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