Po4 and continuous water change questions

[Randy Holmes-Farley]

Thanks, Tom.

Here's an article that might be interesting with respect to growth:

http://www.sciencedirect.com/science/article/pii/S0022098111004588#

Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach

They tested phosphate up to 0.5 ppm, and found that the highest growth happened at the highest phosphate concentration.

From it:

"Phosphate concentration produced no visible effects of stress on the corals, as indicated by polyp extension and lack of mortality. It is suggested that the phosphate enhanced growth was due to increased zooxanthellar populations and photosynthetic production within the coral. Skeletal density reduction may be due to phosphate binding at the calcifying surface and the creation of a porous and structurally weaker calcium carbonate/calcium phosphate skeleton. Increased phosphate concentrations, often characteristic of eutrophic conditions, caused increased coral growth but also a more brittle skeleton. The latter is likely more susceptible to breakage and damage from other destructive forces (e.g., bioerosion) and makes increased coral growth a poor indicator of reef health."

 

[Relativity]

I've tried elevated levels of Nitrate in my system but I have some kind of nasty algae that gets out of control. Im not sure what it is or how to get rid of it. I will show you a pick a maybe you will know. When I tried to add nitrate to my tank it attached to many skeletons and killed the coral.
I've tried marin Fauna algae x but after like twenty treatments the stuff just comes back.
Im thinking about doing a blackout on the tank but I think this stuff came from the rock that I used which was dead and I will never get rid of it

 

[waverz]

FWIW, I'm aware of at least one tank that has very beautiful SPS and other hard corals, and it remarkably has nitrate over 50 ppm and phosphate well above 1.0 ppm:

http://www.reefcentral.com/forums/showthread.php?t=2366953

Here's a pic from it:

So clearly there is a lot more to the issue than just the numbers.

Hard to argue with that.

 

[tdb320reef]

Thanks, Tom.

Here's an article that might be interesting with respect to growth:

http://www.sciencedirect.com/science/article/pii/S0022098111004588#

Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach

They tested phosphate up to 0.5 ppm, and found that the highest growth happened at the highest phosphate concentration.

From it:

"Phosphate concentration produced no visible effects of stress on the corals, as indicated by polyp extension and lack of mortality. It is suggested that the phosphate enhanced growth was due to increased zooxanthellar populations and photosynthetic production within the coral. Skeletal density reduction may be due to phosphate binding at the calcifying surface and the creation of a porous and structurally weaker calcium carbonate/calcium phosphate skeleton. Increased phosphate concentrations, often characteristic of eutrophic conditions, caused increased coral growth but also a more brittle skeleton. The latter is likely more susceptible to breakage and damage from other destructive forces (e.g., bioerosion) and makes increased coral growth a poor indicator of reef health."

Very interesting--> Faster growth but lower density.

 

[dkeller_nc]

I've tried elevated levels of Nitrate in my system but I have some kind of nasty algae that gets out of control.

I think I'd be more concerned with the Aiptasia population than the algae. But there are some types of algae that really don't respond too well to low NO3 and/or low PO4. Perhaps this is the case with your tank.

 

[tmz]

Thanks for the article Randy. Iv'e read it a few times.

Here is another on coral growth which I thought was helpful particularly some of the sections on calcium delivery to the skeletal matrix and the role attributed by the authors to zooxanthelae and ATP in that process:

http://www.coralscience.org/main/articles/biochemistry-2/how-reefs-grow


I like Thales's tank a lot but have some questions about it. Age? Time frame for the 1+ppm PO4 and very high NO3? and a few others. No doubt it's a beauty though. I've posted on his thread but have avoided any commentary that might be perceived as negative since I think on the whole the effort in the thread and the article he co authored affords positive counterpoint the fear of a little PO4 that may show up in a test and may help lessen harmful overreactions . I've seen the negative effects of chasing 0 PO4 and 0 NO3 .

Anecdotally , my personal experience has been different than that tank. When I ran my tanks without much regard for NO3(50 ppm) or PO4(0.3ppm plus) I could get some good growth and good results for a year or more for some of the sps but not all of them and then on several occasions problems started;stn, coral bowning , receding tissue in lps and sps ,some deaths ,algae out breaks etc. Coincidence? Maybe . However, since controlling PO4 and NO3 via soluble organic carbon dosing,there has been none of that for the past 5 years. Even some very difficult smooth skinned acros thrive along with other species . Coral growth and color are very good too. I agree it's much more than chasing the numbers and there are many variables and contexts. But ,I still think paying attention and managing PO4 and NO3 levels are worthy efforts for my tanks anyway. I agree that a recommendation to keep PO4 low is usually a good one.

 

[Randy Holmes-Farley]

It is surprising that Richard's tank does so well with high PO4. It may be iron limited and others are not, giving different experiences. Or it may be different for reasons we do not understand. But I accept that his tank has had elevated PO4 for a substantial period (more than a year) and that the tests he has used are accurate enough to think that PO4 is very high.

 

[tmz]

I accept his expertise and integrity and said so in his thread and another in the sps forum as others attacked it. My questions are driven by a lack of understanding of what's going on and an effort to dig into the details for a clue ,not so much at the sub 0.5ppm level but more so at the much higher levels. Beyond my reach ,at least for now , I guess. FWIW, iron in my sytem is very low per the Red Sea test and could be limiting. It seems to be for red turf algae ,since when I dose it that increases and wanes without dosing.

 

[Relativity]

I would watch out with the red sea kits for iron and iodine, when they get old and give low readings from my experiance

 

[Relativity]

Anecdotally , my personal experience has been different than that tank. When I ran my tanks without much regard for NO3(50 ppm) or PO4(0.3ppm plus) I could get some good growth and good results for a year or more for some of the sps but not all of them and then on several occasions problems started;stn, coral bowning , receding tissue in lps and sps ,some deaths ,algae out breaks etc. Coincidence? Maybe . However, since controlling PO4 and NO3 via soluble organic carbon dosing,there has been none of that for the past 5 years. Even some very difficult smooth skinned acros thrive along with other species . Coral growth and color are very good too. I agree it's much more than chasing the numbers and there are many variables and contexts. But ,I still think paying attention and managing PO4 and NO3 levels are worthy efforts for my tanks anyway. I agree that a recommendation to keep PO4 low is usually a good one.

I have read the same thing somewhere I can't remember from where that corals are more susciptible to sickness from elevated levels of No3 po4. Sorry I can't source what Iam talking about, but your conclusion also confirms.

 

[Randy Holmes-Farley]

This might pertain to the discussion:

Impacts of nutrient enrichment on coral reefs: new perspectives and implications for coastal management and reef survival

http://www.sciencedirect.com/science/article/pii/S1877343513001917

Anthropogenic nutrient enrichment is often associated with coral reef decline. Consequently, there is a large consent that increased nutrient influxes in reef waters have negative longterm consequences for corals. However, the mechanisms by which dissolved inorganic nutrients can disturb corals and their symbiotic algae are subject to controversial debate. Herein, we discuss recent studies that demonstrate how nutrient enrichment affects the heat and light stress tolerance of corals and their bleaching susceptibility. We integrate direct and indirect effects of nutrient enrichment on corals in a model that explains why healthy coral reefs can exist over a rather broad range of natural nutrient environments at the lower end of the concentration scale and that anthropogenic nutrient enrichment can disturb the finely balanced processes via multiple pathways. We conceptualise that corals can suffer from secondary negative nutrient effects due to the alteration of their natural nutrient environment by increased phytoplankton loads. In this context, we suggest that phytoplankton represents a likely vector that can translate nutrients effects, induced for instance by coastal run-off, into nutrient stress on coral reefs in considerable distance to the site of primary nutrient enrichment. The presented synthesis of the literature suggests that the effects of nutrient enrichment and eutrophication beyond certain thresholds are negative for the physiological performance of the coral individual and for ecosystem functioning. Hence, the immediate implementation of knowledge-based nutrient management strategies is crucial for coral reef survival.