1. Modern Reef Keeping - Chemistry

2. Modern reef keeping Optimal water parameters for reef keeping
Life support
Temperature
Oxygen
Salinity
pH/Alk
Introduction to skeletogenesis
Ca, Alk, Mg
Typical syndromes in aquarium
Secondary elements
K, I, Sr, Fe
Nutrients, Pollutants & Algae
PO4 / NO3 /SiO4
Sources
Typical algae in reef tank

3. All biological processes occur in aqueous environment
Life support parameters- Temperature, Salinity, Oxygen and pH/Alkalinity.
All biological processes occur in aqueous environment
Temperature
Salinity
Dissolved Gasses pH

4. Life support parameters- Temperature
Water temperature in the tropic’s range : °C (NOAA,WOA98)

5. Life support parameters- Temperature
One of the most crucial water parameter in the reef environment with direct impact on:
Dissolved gases and their saturation
Inhabitance’s metabolism
Accuracy of S.G. and pH measurements.
The Key is Stability - Temperature fluctuations of more than 2°C are the main reason for coral bleaching
Water temp. rise in 2 degrees

6. Life support parameters- Temperature
Recommended temp in a reef tank: 26-27°C
Closer to natural temp. at most areas where corals are collected from.
Increase metabolism= rapid growth and better immune response

7. Life support parameters- Oxygen
Oxygen levels in coral reefs (ppm)
DO levels in coral reefs: mg/l with 80% saturation (NOAA,WOA98)

8. Life support parameters- Oxygen
Dissolved Oxygen
DO is temperature and salinity dependent.
As long as the DO levels are in saturated/ slight below super-saturated , the reef inhabitance can tolerate higher temperature (28-29°C)
Saturated oxygen levels prevent dissolved CO2 buildup and pH drops.

9. Life support parameters- Oxygen
Dissolved Oxygen
Increasing DO:
Protein skimmer
Surface skimmer
Water surface agitation
Can be measured with colorimetric test kit or non-directly but very efficient with RedOx meter.
Super saturation =Micro-bubbles

10. Life support parameters- Salinity
Salinity levels in coral reefs (ppt)
salinity levels in coral reefs: (ppt) (NOAA,WOA98)

11. Life support parameters- Salinity
Salinity is the summery of all the dissolved salts mass in volume of water and it is measured as ppt = g/L = ‰ =psu, with refractometers or Conductivity meters (mS).
Specific Gravity is the densities ratio
between salt water solution and the
same volume of pure water at 4°C
S.G. doesn’t have units, measured by
hydrometer and it is temp. dependent!!!
Salinity affects marine organisms because the process of osmosis.
Na & Cl concentration in the aqueous medium has direct influence on marine organisms metabolism – Coral calcification.
Recommended salinity in reef tank: ppt for optimal calcification.

12. Life support parameters- pH.
pH levels in coral reefs:

13. Life support parameters- pH/Alkalinity
pH and dissolved CO2
All biological processes occur in specific
narrow range of pH.
Optimal Calcification pH: 8.3
Optimal ammonia removal
from gills: (marine fish).
Optimal level for reef tank:
pH levels major influential factor is CO2- alkalinity
CO2 + H2O <=> H2CO3 <=> H+ + HCO3- <=> 2H + + CO32-
In sea water: (1%) (93%) (6%)
How to prevent pH drops:
Stable alkalinity (buffer) meq/l
Protein skimming
Water agitation
Organics removal

14. Introduction to Skeletogenesis or coral Calcification
The site : Coral polyp
The lead stars : Ca⁺², HCO₃⁻
The co-stars: Mg ⁺², H ⁺, CO₂, Sr ⁺²
The director: Zooxanthellae
Special effect: Light

15. Introduction to Skeletogenesis or coral Calcification
Coral Tissue
Sea Water
The Zooxanthellae takes CO2 from coral respiration and from HCO3- and convert it to carbohydrates
In low concentration
Mg ⁺
HCO3-
Ca⁺²
Passive diffusion
HCO3-
The Carbohydrates are used as fuel for the active transporters
g ⁺ ⁺²
Active diffusion
HCO3-
Ca⁺²
HCO3-
Ca⁺² Mg
HCO3-
Ca +2 Mg
Coral skeleton = Aragonite

16. Introduction to Skeletogenesis or coral Calcification
Balanced levels at pH =8.3 Salinity = 33 ppt
Ca⁺² ppm
Alk
Mg⁺² ppm
Fish
380
2.5-3
7-8.5
1150
Soft
400
3-3.5
8.5-10
1200
LPS
425
3.5-4
10-11
SPS
455
4-4.5
1350
SPS COLORS
430 3
8.5
1300
Optimal conditions for skeletogenesis:
Creating positives ionic gradient from the surrounded water to the inner coral layers.
Balanced quantities of the building blocks.
Proper pH and Salinity
Energy source

17. Introduction to Skeletogenesis or coral Calcification
The Key = Balance ?

18. Introduction to Skeletogenesis or coral Calcification
The role of Magnesium:
“The Buffer “ of the buffer = MgCO3-
Controls precipitation
Controls CaCO3 crystallization = skeletal strength
Important co-factor in zooxanthellae photosynthesis. Mg

19. Introduction to Skeletogenesis or coral Calcification- Typical Reef Syndromes:
Area
Explanation
Reasons
Solution 1
High Alkalinity Low Calcium (usually low pH)
Unbalanced salt mixes
Unbalanced A+B supp.
Ca reactor adjustment
Success calcium
CaOH
15% water change with CP salt. 2
Low Alkalinity Low Calcium (usually low pH)
Low salinity
Low magnesium
CP salt
Reef Gro Kit
Calk
Reducing lighting hours 3
Low Alkalinity High Calcium
Success Coral Buff & Magnesium
Stop CaOH if used 4
High Alkalinity High Calcium
High salinity
Wrong additives calculation
Time
Increase lighting hours and currents to accelerate calcification.

20. The role of other important major, minor and trace elements:
Many other elements are used as co-factors in many biological processes. The most important are those that must be replenished on regular basis.
K⁺ - Zooxanthellae nutrient, promotes red/pink/ Purple pigments. Incorporate with active membrane transportation pumps (Na/K)
Sr⁺² - Increase skeleton strength by controlling the formation of aragonite instead of calcite (Like magnesium)
Fe⁺³/Mn⁻² - Important photosynthesis co-factor, Zooxanthellae nutrient, promotes Green pigments. Important co-factor in de-nitrification.
I-- Important antioxidant , control Photosynthetic oxygen radicals in Soft and LPS corals. Promote pigments formation and reduce bleaching by UV shock.

21. Pollution and pollutants
Coral reefs develop and flourish only in oligotrophic ocean areas with clear, unpolluted with limited nutrients in the water.
In the natural reef environment, the major nutrients N, P, C are only available for the zooxanthellae (Coral symbiosis)
Pollution – When the nutrients reach to a certain levels they stop being the limited factor in the reef system.
High nutrient levels enhances
bacteria proliferation and algae
bloom- Eutrophication.

22. Pollutants - N

23. Pollutants - N In natural corals reef: NO₃⁻. < 0.3ppm
Nitrogen forms in the aquarium: NH₃/NH₄⁺, NO₃⁻.
Sources: Organic mater decomposition, fish extracts, tap water, supp., salts, live rocks, coral sand.
Negative effects of high nitrate levels:
Indirect damage to corals by Increasing zooxanthellae densities
Competition with the coral on carbon source (HCO₃⁻)
Intensive photosynthesis – high levels of oxygen radicals.
Coloration
Eutrophication –nuisance algae outbreak.
Treatments
10-15% weekly water change
NO₃⁻ absorbers –zeolites
Assimilation - Refugium
Enhancing De – nitrification

24. Pollutants – N – De nitrification
De – nitrification - Microbial process of nitrate reduction to nitrogen gas.
Made by at least 10 facultative heterotrophic bacteria strains at anoxic levels – not anaerobic !
ppm< O₂< 0.2 ppm
0>ORP> -180 mv
12NO₃⁻ + 10CH₃OH+ 12H⁺-> 6N₂+10CO₂ +26H2O
Carbon source is the limited factor of the process (also Mo and Fe).
Light inhibit de-nitrification
The process occur naturally in live rocks pores and in the lower sediment (after 3 weeks from starting the cycle)
Filtration methods to control/ enhance de-nitrification:
De-nitrators
Assimilation - refugium
DSB/ Plenum

25. Pollutants - P

26. Pollutants - P Phosphate forms in marine environment : PO₄³⁻, HPO₃²⁻.
Sources: Organic mater decomposition, fish extracts, tap water, supp., salts, live rocks, substrate.
In corals reef: PO₄⁻. < 0.05 ppm
Negative effects of high phosphate levels:
Direct damage to corals by reducing available Ca ions for coral skeletogenesis. Ca3(PO4)2 formation inhibit CaCO₃ lattice formation.
Increase zooxanthellae densities.
Eutrophication – Cyanobacteria – Toxins.
Treatments
10-15% weekly water change
PO₄³⁻ absorbers (FeO/OH, FeCl, AlO)
Assimilation - Refugium
Microbial reduction – carbon source.

27. Pollutants - Si
Silicon forms in marine environment : Si(OH)4. Si(OH₃)o.
Sources: tap water, supp., salts, live rocks, substrate.
In corals reef: Si(OH)4 < 0.5 ppm
Important nutrient for sponges and snails.
High level can cause diatoms outbreak for several days.
Treatment:
10-15% weekly water change
Si(OH)4 absorbers (FeO/OH, FeCl, AlO)
Assimilation – Refugium with sponges
Do nothing- it will leave as it comes.

28. Pollution- The magic circle of polluted tank.
Pollution – When the nutrients reach to a certain levels they stop being the limited factor in the reef system. High nutrient levels enhances bacteria proliferation and algae bloom- Eutrophication
Organic matter:
Fish food and extracts, Dead Bacteria and micro-algae, Coral tissues and mucus
NO3
Algae
+ Oxygen
P04
Bacteria
Organic matter decomposition reduce dissolved oxygen

29. Pollution- Oxygen demand and RedOx
Many biological process can described as Reduction/Oxidation processes where electrons are transferred from one element to the other.
Oxidation – nitrification - NH₃ + O₂ -> NO₃⁻
Reduction –De nitrification - NO₃⁻ + C -> N₂
All decomposition process requires oxygen as the oxidizer- therefore the oxygen levels will drop followed by a drop in RedOx level (mV).
Increasing the oxygen levels, by removing the organic material out of the system, will increase the RedOx potential.
How to increase RedOx in the reef aquarium:
Good protein skimmer – takes the organics out and insert oxygen.
Ozone- break down organics and oxidize water.

30. Pollution-Eutrophication of Nuisance algae
Nuisance algae – undesired micro-algae or desired algae in un controlled growth (Macro algae).
Micro-algae:
Green hair algae
Blue-Green – Cyanobacteria
Diatoms
All the three will appear naturally during the cycle period.
Macro-algae:
Caulerpa sp.
The dangers of eutrophication :
Competition on nutrients with zooxanthellae & coralline algae
Competition on space
Corals suffocation and shading
Toxins – alleochemicals
Oxygen reduction during the dark periods
Oxygen super saturation during the light hours

31. Pollution-Eutrophication of Nuisance algae
Nuisance algae – Green algae
Most common: Bryopsis, Debresia, Valonia.
Circumstances for outbreak:
Organics accumulation
High nitrate, phosphate and iron levels
Strong lights not with the adequate PAR and color (to much red) or old bubbles.
Damage:
Competition on nutrients with zooxanthellae and coralline algae
Competition on space
Corals suffocation and shading
Oxygen reduction during the dark periods
Oxygen super saturation during the light hours
Treatments:
Organics removal – Protein skimmer
Nutrient reduction - biological processes
Assimilation – Macro-algae refuigium
Physical trimming
Fixing lights issues

32. Pollution-Eutrophication of Nuisance algae
Nuisance algae – Blue green - Cyanobacteria
One of the oldest life forms.
Circumstances for outbreak:
Organics accumulation
Unbalanced N : P ratio or high Phosphate – assimilate nitrogen from atmosphere
Damage:
Toxins
Competition on space
Corals suffocation and shading
Oxygen reduction during the dark periods
Treatments:
Organics removal – Protein skimmer
Phosphate reduction - biological processes.
Assimilation – Macro-algae refuigium
Physical removal

33. Pollution-Eutrophication of Nuisance algae
Nuisance algae – golden brown - Diatoms
Circumstances for outbreak:
Silicates
Damage:
Nothing
Treatments:
Patient !
If it’s continues- check for Si in the fresh water source.

34. Pollution and pollutants-Summery
Organics
Reduce oxygen
Increase bio - load
Increase nutrients
Suffocation
toxins
Calcium accessibility
Damage to corals and fish
Algae outbreak
Suffocation,
Toxins, competition with Zooxanthellae

35. Thank you for listening!!!
God help us, it’s only the second lecture and we have another 3…