[ShaunW]

There are many different combinations of equipment and husbandry to lead to the final achievable goal of colorful and rapidly growing SPS.

To sum up success in two words IMO: Phosphate control.

Inorganic phosphate inhibits calcification. Stop calcification and you decrease/stop growth which decreases color.

How you decrease phosphate really doesn't matter, i.e. skimming, water changes, phosphate absorption, etc; as long as you come close to the magic level (Redfield ratio) found in nature.
http://en.wikipedia.org/wiki/Redfield_ratio

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[ShaunW]

MARINE BIOGEOCHEMISTRY: ON REDFIELD RATIOS

The following points are made by P.G. Falkowski and C.S. Davis (Nature 2004 431:131):

1) An interesting empirical observation in biology is the relationship between the elemental composition of organisms and ecosystems. All organisms are composed primarily of a mixture of six major elements: hydrogen, carbon, nitrogen, oxygen, phosphorus and sulphur. But the proportion of these basic ingredients varies between organisms -- and such variations can lead to interesting properties within ecosystems.

2) For example, in the oceans most of the biomass comprises small drifting organisms (plankton) that are rich in nitrogen. These organisms are essentially functionally similar ensembles of metabolites, often encased in a shell formed from the most readily available ingredients. Much plankton is consumed by other plankton with similar chemical compositions. The result is that on average, the nitrogen: phosphorus (N:P) ratios of plankton in the oceans are remarkably similar throughout the world, averaging approximately 16:1 by atoms. When these organisms or their body parts sink into the ocean interior, their energy-rich bodies are consumed by bacteria which, in aerobic conditions, oxidize the organic matter to form dissolved inorganic nutrients, especially CO2, NO3(-) and PO4(3-).

3) In 1934, Alfred Redfield (1890-1983) wrote a now classic paper in which he proposed that the N:P ratio of plankton (16:1) causes the ocean to have a remarkably similar ratio of dissolved NO3(-) and PO4(3-). This hypothesis suggested that, devoid of life, the chemical composition of the oceans would be markedly different. The concept of Redfield ratios has been fundamental to our understanding of the biogeochemistry of the oceans ever since.

4) The basic problem with Redfield ratios is that they are empirical. The ratios were originally derived from measurements of the elemental composition of plankton, and the NO3(-) and PO4(3-) content of seawater from a few stations in the Atlantic, but were subsequently supported by hundreds of independent measurements. Yet there is no known reason why the average N:P ratio of plankton should be 16:1. Why not 6:1? Or 60:1? If one looks at the elemental composition of individual species of phytoplankton grown under nitrogen or phosphorus limitation, the N:P ratio can vary from around 6:1 to 60:1. Redfield understood this problem, but did not try explain it, except to note that the N:P ratio of inorganic nutrients in the ocean interior was an average, and that small-scale variability around the mean was to be expected.

5) Despite many reports that the elemental composition of organisms in a region of the ocean does not conform to Redfield ratios, or that the elemental composition of marine phytoplankton grown in cultures is not 16:1, Redfield's fundamental concept remains valid. It cannot be rationalized by reductionist arguments, nor refuted by anecdotal observations. The fact that the NO(3-):PO4(3-) ratio in the interior of all major ocean basins is remarkably similar to the N:P ratio of plankton is due to the residence times of these two elements in the ocean (roughly 10^(4) years), relative to the ocean's circulation time (roughly 10^(3) years). As the residence times exceed the mixing times by an order of magnitude, it should not be surprising that the NO(3-):PO4(3-) ratios in the ocean interior are remarkably constant.

6) The specific elemental composition that is the Redfield ratio is truly an "emergent" property that reflects the interaction of multiple processes, including the acquisition of the elements by plankton, the formation of new biomass and the remineralization of the biomass by bacteria in the ocean interior, as well as losses of nutrients from the ocean because of burial in the sediments (for example, phosphorus in apatite), or outgassing to the atmosphere (for example, production and loss of N2, due to denitrification).(1-4)

References:

1. Falkowski, P. G. et al. Science 305, 354-360 (2004)

2. Hedin, L. Proc. Natl Acad. Sci. USA 30, 10849-10850 (2004)

3. Redfield, A. C. in James Johnstone Memorial Volume (ed. Daniel, R. J.) 176-192. (Liverpool Univ. Press, 1934)

4. Sterner, R. W. & Elser, J. J. Ecological Stoichiometry: The Biology of the Elements from Molecules to the Biosphere (Princeton Univ. Press, 2002)

Nature http://www.nature.com/nature

[ShaunW]

TO SUMMARIZE the above info and integrate it towards our aquariums:

All living creatures in our tank will be similar to their ocean cousins having a Redfield ratio of 16N:1P. Collectively, they will work to maintain this ratio by either growing or dying as the water chemistry changes (water Redfield ratio changes).

If your water's inorganic phosphate level is high then the equilibrium between the living creatures ratio and the environment's ratio will be dissimilar. Therefore, the living creatures will use the inorganic/free phosphate to bring the ratios back to equilibrium by growing and using up the phosphate. This usually manifests as nuisance algae growth in our aquariums, since they are best at integrating excess nutrients towards replication. They decrease environmental P through growth, bringing the inorganic and organic Redfield ratios back to equilibrium.

Bacterial populations too will increase, but their effects on the entire ecosystem I will leave out, therefore keeping the thought process simpler.

In the case of SPS specifically, the zoox will grow when the environmental Redfield ratio is off (high phosphate), using up the external phosphate similar to other algae species. Since the zoox concentration within an SPS is constant, the host (coral) will not be able to adjust fast enough to deal the the zoox concentration increase. This will lead to many problems, the least of which will be lack of growth and color.

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[tosiek]

i <3 u Solbby. Very interesting and good read on the topic.

[ShaunW]

Thanks!

[fritz]

Shaun you're a sucker. Posts like this just make me want to go buy a tank again. I need to stop reading your posts, you're going to cost me a fortune. Nice info by the way

[autoponicz]

at the moment my sps is light in coloration....theres color but not brilliant......they are not brown at all.....is it because i need more nutrients in the tank?...like feed more or add more fish?

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[jackson6745]

Quote: Originally Posted by ShaunW There are many different combinations of equipment and husbandry to lead to the final achievable goal of colorful and rapidly growing SPS. To sum up success in two words IMO: Phosphate control. Inorganic phosphate inhibits calcification. Stop calcification and you decrease/stop growth which decreases color. How you decrease phosphate really doesn't matter, i.e. skimming, water changes, phosphate absorption, etc; as long as you come close to the magic level (Redfield ratio) found in nature. http://en.wikipedia.org/wiki/Redfield_ratio

BRAVO!

	SPS Small Polyped Scleractinians - Sometimes known as Small Polyped Stony corals. These are hard corals that have extremely small polyps. They are typically on the difficult side and require Metal Halide lighting or dense Power Compact or T5 arrays. These corals are prized for their rareness and ability to be easily fragged into multiple colonies.

[inkblue]

good read...

[ReefnQueens]

awesome read