Water Chemistry ITFS2

8/3/2019 Water Chemistry ITFS2

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Ian Millichip

Water-

Quality and ChemistryIrish Tropical Fish Society

08 March 2011

Water Quality and Chemistry


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Aims1. Emphasise the wonders of water and

some science of water.

2. De-mystify some parts of waterchemistry and show patterns

3. Explain the meaning of common waterquality parameters

4. Show relationship between water qualityparameters

5. Discuss the measurement and relation ofwater parameters to fish health

6. Set a platform for future study



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Overview Water. The Magic

Chemical Directions

Measurements and Meaning

pH/Acidity/Basicity/Alkalinity

pH Buffers

Hardness

Redox

Methylene blue

Nitrogen Cycle and filtration

Water Treatment/Chlorine/chloramine (Conductivity / Salinity / TDS)?



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Some Food for Thought

(first)



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Water Is

Oxidane

An Anomoly

Water Liquid at Room Temp Hydrogen Sulphide toxic gas

Selenium Hydride toxic flammable gas



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Water Is Magical

Great Solvent (but not for water)

Specific heat capacity (High)

Heat of Vaporization ~ Humidity Air Miscibility and condensation /From Ice to Gas Density of Water vs Ice (4 C)

Low Compressibility Cohesion and adhesion

Surface tension (cohesive strength) Capillary action (adhesive strength)



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Water Is

Life

Cradle of Life

Vital Biochemical

Water to Oxygen

Oxygen to Water

Hydrolysis/Catalyst

Substrate

Destroys Cells

Valuable ~a few million for 80litres?



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Chemistry is aboutChanges

But Change cannot be anyold Change.

Chemistry in 3 Human Scenarios



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Change



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Change


In Short..Chemistry is A downhillslippery and messy slopewith

Getting to Equilibriumand

Having MinimumEnergy AND

Giving out the MostUseable Energy

With the MaximumEntropy (=mess orchaos)

HIGH ENERGY

LOW ENERGY


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ChangeRule is:1/3 downstairs



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Getting Down to Business


l d h


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Starting With Getting some water


R.O. Unit

Fish Tank

Water Conditioner

Water/Metals/Chlorine/Chloramine/Salts/Acids/Bases/Carbonates/other moleculesWater/Metals/Chlorine/Chloramine/Salts/Acids/Bases/Carbonates/other molecules

?? What is in it ??

W t Q lit d Ch i t


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Conditioners

DechlorinationSodium thiosulphate (produces ammonia from Chloramides)

Sodium hydrosulphite

Sodium hydroxymethylsulfinate

Sodium hydroxymethanesulfonateHeavy Metal Removal

In some, but not all. Organic or Synthetic Chelating agents.

Slime Coat Protectionaloe vera and other herbals

carboxymethylcellulose

Polyvinylpyrrolidone

Other Additives


W t Q lit d Ch i t


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Acids/Bases et alpHa measure of acidity/basicity

- log10 (Hydrogen ion)

Affected by Temperature / Concentration / ionic strength

Acid

Donate a hydrogen ion to solution (classical understanding); OR

Accepts an electron pair (eg Aluminium Chloride)

Base

Accepts a hyrdrogen ion; OR

Donates an electron pair

pH Buffer

Resists changes of pH on addition of a small amount of acid or base

Often mix of a weak acid or weak base and the salt of a weak acid or weakbase

Alkalinity

Type of buffering. MEASURE..solutions ability to neutalise an acid.

Linked in Aquaria to Carbonate buffering (and hardness)


W t Q lit d Ch i t


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HardnessClassically.Hard to form a lather Temporary Hardness

Easily removed by boiling

heating decomposes soluble Bi-carbonates (Hydrogen Carbonates)to insoluble Carbonates

Permanent Hardness Soluble calcium and magnesium salts

eg Calcium and Magnesium chlorides and sulphates

Removed by Distillation/De-ionisation/Ion Exchange/RO/Chemical Reaction

Measuring.. KH vs GH.depends exactly on what isbeing measured by a Test Kit.GH and KH are NOT chemically or mathematically related.

Different units used in different test (DH. ppm, Clarkes)


Wate Q alit and Chemist


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Hardness Contributes or Affects

General stability

pH

pH Buffering

Alkalinity

RedOx and RedOx Balance

Ionic balance/conductivity/TDS

Diffusion/Osmosis Nutrient Uptake

Supply of vital minerals: calcium & magnesium




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RedOx RedOx = Reduction and Oxidation RedOx Balance is vitally important.Complex RedOx Potential (ORP)

Potential to Donate Electrons (Reducing Environment)

Potential to Accept Electrons (Oxidising Environment)Is just a measure (and askwhat is measured?)

+300 (Ox) to -100(Red) mV (marine); +125 to -200 mV (freshwater) Reducing Environment is ideal for fish health Oxidising Environment is good for sterilising

RedOx balance can get run-down with time. Regular Partial Water changes; good aeration Having a good buffer

Monitoring and maintain pH, Alkalinity, Hardness help.




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RedOx

Vital Consideration The basis of life existing pivots around RedOx Potentials

General Health and Water Quality

In Aquaria(for examples). Exchange across Gills

Interaction at mucous layer

Dropsy/Kidney Function/

Exploitation of substrate buffering

Old-Water syndrome

Biological Filtration Decay upsets RedOx Balance

Treatment of Disease

Treatment of certain poisonings




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Methylene Blue


Key Treatment in Aquaria Stain for microscopy and clinicaldiagnosis

Redox Indicator **

Methaemoglobinaemia / CyanidePoisoning / Carbon MonoxidePoisoning **

** = my academic area of study

Photosensitiser Hepatitis C/ Kaposi's sarcoma/inactivates Staphylococcusaureus

Anti-Malarial Induces Cancer Cell Apoptosis ** Protects against Mustard AlkylatingAgent Neurotoxicity ** Mono Amine OxidaseInhibitorused to make anti-psychotic drugs **

RedOx Agent



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Test Indicators


A pH Indicator (Thymol Blue)

General Hardness Indicator

Nitrte/Nitrate Test



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Acids




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pH (Strong Acid)


Grams HCl ~ pH

3700 1.00

1850 1.30

370 2.00

37 3.00

3.7 4.00

0.37 5.00

0.037 5.96

0.0037 6.70

0.00037 6.96

0.000037 7.00

0.0000037 7.00

0.00000037 7.00

0 7.00

1000 litres

HCl + Pure Water

Hyrogen Chloride (HCl)In water

= Hydrochloric Acid

(1 mole HCl = 36.5g)



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pH (Weak Acid)


1000 litres

HAc + Pure Water

Acetic Acid (HAc)(1 mole HAc= 60g)

pKa = 4.75

Grams HAc ~ pH

6000 2.88

3000 3.03

600 3.38

60 3.88

6 4.38

0.6 4.88

0.06 5.37

0.006 5.85

0.0006 6.290.00006 6.63

0.000006 6.85

0.0000006 6.95

0 7.00

B



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pH (Weak Acid as Buffer)


pKa1 2.1

pKa2 7.2

pKa3 12.4

Baseconj

A

Acidconj

H

Acid

HA aqaqaq

'')(

)()()(

}{

}}{{

HA

AH

Ka

)(10 aa

KLogpK

)}{(10 aKHALogpH



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Nitrogenous Compounds Amino Acids from Proteins >

Building Proteins/ Converted to Fat or Sugars or other biochemicals

Compromise energy and water needs in disposal.

Surplus amino acids need to be excreteddepends upon

the bodys water demands and supply. Reptiles > urates/uric acid with very little water

Marine Fish > dimethyl amine or as urea in blood

In humans > urea dissolved in plenty of water

Freshwater fish > direct movement of ammonia out of gills (mainlyby passive diffusion)

Diffusion of Ammonia out of fish depends on ammonia inoutside water and pH.




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Nitrogenous Compounds


Amino Acids / Waste / Dead fish / uneaten food

In the Aquarium

Ammonia (NH3)

Ammonification

[RAPID]

Nitrosofication(Nitroso-bacteria+Oxygen)

Nitrous Acid/Nitrites (NO2)

Nitrification(Nitro-bacteria+ Oxygen)

Nitric Acid/Nitrates (NO3)

0.06 mg/L

0.5 mg/L

90.0 mg/L



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Ammonia


Total Ammonia = Ammonia + AmmoniumUIA = Ammonia



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Filter Media

Inert{all are mechanical}

Inert Rocks/Pebbles Sponge

Wool Ceramic or special glass chips Membranes {eg Reverse Osmosis; removes selected molecules}

Q y y



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Filter Media (or similar)Active{all are mechanical/ many will allow nitrogenous oxidising activity}

Peat or living moss {^acids; soften; ^ organic compounds} Plants {lower nitrates} Activated Carbon {catalyst; remove certain chemicals} Clay {softens; remove chemicals; add minerals} Calcium Carbonate chips {Redox & Alkalinity Buffer} ## Aluminium oxide or Ferric oxide base.{Phosphate} ## Denitrifying Modified Beds {Nitrate Removal}

Sulphur-source or Carbon-source added Deep anaerobic filter bed

# Zeolites/Molecular Sieves {remove ammonia etc;removes and exchanges various ions}

# = Care - nutrient hazard ## = Extra Care - toxic hazard

Q y y



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Ammonia + Chlorine + HCl Chloramines

Ian Millichip

RO System & Chloramines

Q y y

~ pH

Activated

Carbon(Low Peroxide No.)

pH > 7.5

Ammonia (UIA)

ToRO Unit

Ammonia + ^pHLower pH >AmmoniumAnd reduceMembraneSwelling

RO Membrane



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ll h

Summary1. No amount of Knowldege can make up for poor Water

Management.2. Water Chemistry iscomplex

Standard Text Book chemistry does not necessarily apply

3. Water Chemistry is not an option. !! You may not want to know it.

But your Fish DO.4. Do not mess with Water Chemistry unless one

understands the implications5. Understanding the complexity may help explain

unexplained6. Know the requirements of your fish

7. Linking the Science to the Experience will help developAquatic Husbandry

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Documents

Water Chemistry ITFS2