Can Phosphate levels be too low for Coral growth?

[Bryan]

Tried GFO a number of times over the years and the result has always been the same, corals stop growing, fade in color and a few sucumb to STN, especially digitata and caps.

Could I be driving phosphate to such a low level that it is causing distress to the corals.

Without GFO , phosphate tests out at 0 on the Salifert test, I know Salifert is not the greatest kit for measuring low levels of phosphate.

Nitrate is always ~0 according to my Lamotte Nitrate test kit. I actually dose weekly with potassium nitrate to add a small amount of nitrate to the water column.

Other parameters are fine
Alk 3.2
Ph ~8.2
Salinity 1.026
Calcium 410

Carbon 24/7 and ozone is used. Comments. Anybody else experience the same.

 

[kev apsley]

The modern study of the physiology of coral symbiosis began with a series of elegant experiments done by C. M. Yonge on the Great Barrier Reef Expedition of 1929. Yonge showed that symbiotic corals take up phosphates and ammonia from the surrounding seawater by day and release them at night. In order to study this phenomenon in greater detail two of us (Thomas F. Goreau and Nora I. Goreau) supplied carbon in the form of the radioactive isotope carbon 14 to reef corals. During the daylight hours the zooxanthellae assimilated the radioactively labeled carbon and photosynthetically fixed it into organic matter at a rate that was dependent on the intensity of the light. Some of this organic matter was then "leaked" from the algae to the coral host. Subsequent work by Trench and Leonard Muscatine of the University of California at Los Angeles and by David Smith of the University of Oxford showed that the leaked compounds include simple nutrients such as glycerol, glucose and amino acids. These compounds are utilized by the coral polyps in energy-yielding metabolic pathways or as building blocks in the manufacture of proteins, fats and carbohydrates.

It has long been known that the rates of metabolic reactions are strictly limited by the rates at which waste products are removed from the immediate environment. In higher animals the task is accomplished by specialized circulatory and excretory systems. These systems are absent in the anatomically simple coelenterates, which rely largely on the slow process of diffusion to remove soluble inorganic waste products such as carbon dioxide, phosphates, nitrates, sulfates and ammonia. The zooxanthellae, however, need for photosynthesis the very substances the coral polyp must get rid of, and they are believed to actively take them up from their host

 

[kev apsley]

interesting read

http://www.globalcoral.org/corals_and_coral_reefs.htm

 

[glassbox-design]

yes it's very possible. po4 is needed for corals to live. shoot for .02-.04. if you're running that low nutrient you may want to look into a hanna colorimeter to get more accurate po4 measurements.

how has the potassium nitrate been working in your system? are you adding it as a nitrogen source as well as K?

eric

 

[Sk8r]

That is actually one of the clearest explanations I have read.

 

[kirstenk]

I don't know but I do know that my tank is PO4 Limited. 0.00 on a Hanna ColorMeter for over a year. Whatever PO4 I have is being consumed very fast. I have tried feeding more and this just causes Nitrates to climb.

I feel its a problem but I have no idea what to do about it.

 

[kev apsley]

<a href=showthread.php?s=&postid=10392201#post10392201 target=_blank>Originally posted</a> by kirstenk
I don't know but I do know that my tank is PO4 Limited. 0.00 on a Hanna ColorMeter for over a year. Whatever PO4 I have is being consumed very fast. I have tried feeding more and this just causes Nitrates to climb.

I feel its a problem but I have no idea what to do about it.

do you dose Amino Acids?

 

[Horace]

What are you doing to bottom out the po4? If your using media, just use less.... if your using carbon source, then change up your dosing some. Getting more Po4 is truely not a hard thing to do

Oh and unless your no3 are sky high, I wouldnt worry about those either. no3 are pretty harmless it seems. I have seen some truely amazing SPS tanks with no3 ~50ppm! I always thought they would brown the corals out, but so long as Po4 is low, that just isnt the case.

 

[kirstenk]

Getting more Po4 is truely not a hard thing to do.

One would think.


I use Prodibio and AA are in the ReefBooster. I just started trying to tweak the dosage so I'll see where that gets me. I've heard that oyster eggs are loaded with PO4 so maybe I'll try them.

....nitrates are 10ish, after all the heavy feedings and I would agree, they don't seem to influence color at that level.

 

[jamesdawson]

Fauna Marin just released a GFO that keeps your PO4 level at .04 so you don't go to low. Aquarium Obsessed sells it and its reasonably priced!

James

 

[Bryan]

Yes, I am adding the Potassium nitrate as a source of N. I add about 3-5 grams twice a week. This raises my N to about 5 ppm but it is quickly used up in a day or so. It has imroved the growth of my Chaeto, unfortunately also incresed the growth rates of Valonia as well.

My rational behind adding KNO3 was to increase macroalgae growth which should cause a export of phosphate as well. I think it has worked too well when combined with GFO as the corals appear to be suffering.

I took the GFO off when i posted this thread and in a week I can honestly say the corals are looking better, however there has been an increase of algae growing on the glass at probably twice the rate.

<a href=showthread.php?s=&postid=10391734#post10391734 target=_blank>Originally posted</a> by Flint&Eric
yes it's very possible. po4 is needed for corals to live. shoot for .02-.04. if you're running that low nutrient you may want to look into a hanna colorimeter to get more accurate po4 measurements.

how has the potassium nitrate been working in your system? are you adding it as a nitrogen source as well as K?

eric

 

[Wiskey]

<a href=showthread.php?s=&postid=10393416#post10393416 target=_blank>Originally posted</a> by kirstenk
Getting more Po4 is truely not a hard thing to do.

One would think.


I use Prodibio and AA are in the ReefBooster. I just started trying to tweak the dosage so I'll see where that gets me. I've heard that oyster eggs are loaded with PO4 so maybe I'll try them.

....nitrates are 10ish, after all the heavy feedings and I would agree, they don't seem to influence color at that level.

You might want to try feeding more Nori specifically,.. or Phyto,.. both of those products are loaded with Phosphate.

I notice a big difference in my tank from when I do and don't feed Nori, in both color and growth.

Whiskey

 

[Bryan]

I would be skeptical about that claim from Fauna Marine.

<a href=showthread.php?s=&postid=10423559#post10423559 target=_blank>Originally posted</a> by jamesdawson
Fauna Marin just released a GFO that keeps your PO4 level at .04 so you don't go to low. Aquarium Obsessed sells it and its reasonably priced!

James

 

[Lobster]

This will sound silly, but I had this exactl problem. Quite severely actually, to the point my monitpora would "dry up" and not recover. Acros would grow extremely slowly, but never color up. I tried everything (including a ridiculous goose chase with potassium dosing) and finally found something that worked... the filth reactor!

My state of the art filth reactor is a 3G tank I found in the petsmart bargain bin. I set it up with sand, put a bunch of macro and messy critters in it, and kept it good and filthy (ie, moderately high nutrients). I'm able to "dose filth" into my bare bottom tank by dripping water into the 3G tank and let it flow back to my main tank's sump.

The reason it has worked well for me is that the two systems are not connected, so what happens in the filth reactor stays in the filth reactor. Unless I don't want it to.

 

[glassbox-design]

lobster, that's actually a pretty neat idea...a constant drip of nutrients that's controlable.

 

[govertical19]

This will sound silly, but I had this exactl problem. Quite severely actually, to the point my monitpora would "dry up" and not recover. Acros would grow extremely slowly, but never color up. I tried everything (including a ridiculous goose chase with potassium dosing) and finally found something that worked... the filth reactor!

My state of the art filth reactor is a 3G tank I found in the petsmart bargain bin. I set it up with sand, put a bunch of macro and messy critters in it, and kept it good and filthy (ie, moderately high nutrients). I'm able to "dose filth" into my bare bottom tank by dripping water into the 3G tank and let it flow back to my main tank's sump.

The reason it has worked well for me is that the two systems are not connected, so what happens in the filth reactor stays in the filth reactor. Unless I don't want it to.

I know this is a old tread, but I was wondering if anyone else is have this issue, or has made this filth reactor? I am having the same problem. Phos go between .02 & .05 and some corals are ok nut most acros just die off eventually. I feed a good amount. Full sheet of nori by hand twice or so a day and a automatic feeder that comes on 2 times a day. All my other stats are in-line but I seem to have a problem with most acros..

 

[Nano sapiens]

Without getting to deep into phosphate types and conversions back-and-forth...

As you probably know our test kits can only test for inorganic phosphate. If you are feeding a lot of veggie product, and not much meaty food, then you are adding mostly inorganic phosphate (algae and plants take up inorganic phosphate). It is possible that organic phosphate, which is the main type of phosphate our corals need, may be limited.

Are your Acros going pale and eventually STN'ing? This would be a sign of nutrient starvation and could be countered by spot feeding something like oyster feast, rod's food, etc. a few times a week.

 

[govertical19]

Without getting to deep into phosphate types and conversions back-and-forth...

As you probably know our test kits can only test for inorganic phosphate. If you are feeding a lot of veggie product, and not much meaty food, then you are adding moactually just bought rods food today because I got a blue throat trigger today. inorganic phosphate (algae and plants take up inorganic phosphate). It is possible that organic phosphate, which is the main type of phosphate our corals need, may be limited.

Are your Acros going pale and eventually STN'ing? This would be a sign of nutrient starvation and could be countered by spot feeding something like oyster feast, rod's food, etc. a few times a week.

Yes that is what is happening! Thank you for that answer that makes complete sense to me! I feed alot but as you said it is mainly algae, pellets, etc. I do put zeo coral snow but I do not think that feeds the coral like spot feeding would. does rods food have coral food? I actua

 

[Nano sapiens]

The standard Rod's food has large and small particles, so it can be used to feed fish and just about any coral. Oyster feast is an example of a very small food that can be eaten by SP, Zoas, etc.

How many fish do you have and how big is the tank? Fish waste is an excellent food for corals and some tanks with enough well fed fish don't even have to feed them to get good color and growth.

I spot feed my SPS 2x/week since I have a medium fish load and high export rate of detritus (which basically means a high removal rate of the substance that has, or leads to, phosphates in the water column). I use a mixture of Rod's, baby brine shrimp and Brightwell's Zooplanktos-M, but there are many other tiny foods that could be fed, too.

Each tank is different and you'll need to experiment a little to find just the right balance of export vs import of phosphate, while maintaining a low PO4 level that benefits the corals, but doesn't encourage algae growth.

 

[govertical19]

Lol that is were I get a little confused. My system is pretty big. I have a 265 gallon a 75 gallon and a sump. I have a a pretty good amount of fish too.

6 larger tangs
2 wrasse
2 little Bartlett
3 chromis
Watchman goby
Blue spotted jaw fish
In the 265

4 clown fish
1 kole tang
In the 75

Overall I guess not that many for the size. I got about 12 fish coming this week not including the male blue jaw I just got.

I been dosing some zeo products which I would have figured would have helped.

Zeobac
AA
Coral vitalizer
Coral snow
This week I started coral booster and flatworm stop, which I have read people using with out AEFW. Also the past couple weeks I have been dosing potassium from Brightwell.

I use gac which I have been replacing biweekly. Large skimmer reef octopus 5000 with 3 next extension. Also have biopellets but only about 200ml.

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