Pond Water Quality (the basics)

Frank HenningUGA Watershed Extension Agent

To a great extent water To a great extent water quality determines the quality determines the success or failure of a success or failure of a

fish operationfish operation

• EatEat

• BreatheBreathe

• Excrete wastesExcrete wastes

• ReproduceReproduce

• Take in and lose saltsTake in and lose salts

Fish live in waterFish live in water

Water Quality Factors

• Oxygen/CO2

• Alkalinity, Hardness & pH

• Sediment• Nutrients (NH3 and P)

• Temperature

Dissolved OxygenDissolved Oxygen

• ImportanceImportance– highest cause of mortalityhighest cause of mortality

• Safe levelsSafe levels– greater than 5 mg/Lgreater than 5 mg/L

• Dense bloom, bloom die-offDense bloom, bloom die-off

herbicide app. & turnoverherbicide app. & turnover

Daily O2, CO2 Cycles

DO Management

Avoid OverfeedingMaintain Proper DensitiesAvoid Over-fertilizationIntelligent Weed ControlMonitor Inflow Quality

Outlet Design

Signs of Low DO• Fish not eatingFish not eating

• Piping & GaspingPiping & Gasping

• Groups of Fish at InflowGroups of Fish at Inflow

• Poor GrowthPoor Growth

• Frequent Disease/Parasite OutbreaksFrequent Disease/Parasite Outbreaks

7

6

5

4

3

2

1

05 pm 10 pm 5 am

Measured values

Projected values

mg/l

ProjectedDissolved Oxygen Levels

Lethal

Problem Suspected

Monitor DOProvide Aeration & Circulation

TemperatureTemperature• Effects

– metabolic rate doubles

for every 18oF increase

– Influences spawning

– Influences growth

• Water Density– Max @ 39o F

– Turn- over

Fish Categories – coldwater – coolwater - warmwater

pHpH

• Measure of the hydrogenMeasure of the hydrogen ion concentrationion concentration• 1-14 scale1-14 scale

– less than 7 acidicless than 7 acidic–greater than 7 basicgreater than 7 basic

• Safe rangeSafe range–6.5 - 96.5 - 9

HardnessHardness• Hardness if the measure of Hardness if the measure of

divalent cationsdivalent cations– calciumcalcium

– magnesiummagnesium

• Hardness is used as an Hardness is used as an indicator of alkalinity but indicator of alkalinity but hardness is not a measure hardness is not a measure of alkalinityof alkalinity– magnesium or calcium magnesium or calcium

sulfate increases hardness sulfate increases hardness but has no affect on but has no affect on alkalinityalkalinity

• Recommended hardness Recommended hardness levels > 20 ppmlevels > 20 ppm

AlkalinityAlkalinity• Alkalinity is the capacity of water to buffer Alkalinity is the capacity of water to buffer

against wide pH swingsagainst wide pH swings

• Acceptable range 20 - 400 mg/L Acceptable range 20 - 400 mg/L

Liming PondsLiming Ponds•Total Alkalinity > 20 ppmTotal Alkalinity > 20 ppm

•Agricultural LimeAgricultural Lime

~ every 2 – 4 years~ every 2 – 4 years

• Broadcast Over theBroadcast Over the

Entire Pond SurfaceEntire Pond Surface

•Professional LimingProfessional Liming

Barges on Large PondsBarges on Large Ponds

Total Alkalinity Lime/Surface Area

12 mg/l12 mg/l 1-2 ton1-2 ton

12 - 14 mg/l12 - 14 mg/l 1 ton1 ton

15 - 25 mg/l15 - 25 mg/l 1/2 ton1/2 ton

25 mg/l or more25 mg/l or more NoneNone

Guidelines forGuidelines forApplication of Lime in PondsApplication of Lime in Ponds

Proper FertilizationProper Fertilization

Improper Fertilization, # 1 Cause of Most Problems

•5-10 apps per year

•Start in February

•Time apps using secchi disk

•Shade out weeds

Fertilization Fertilization SupplementsSupplements

the Food Chain the Food ChainMore Fish - Not More Fish - Not Bigger FishBigger Fish

Multiplies the Base Multiplies the Base of the Food Chainof the Food Chain

Increases Carrying Increases Carrying Capacity 4XCapacity 4X

Using the Secchi DiskUsing the Secchi Disk•Professional Disk $25

•Measures visibility

•Measure frequently

•Pie pan, 5 gal bucket lid w/ weight.

Granular Fertilizer ApplicationsGranular Fertilizer Applications

•Usually applied usingUsually applied using

a platforma platform

•Upper end of pondUpper end of pond

Liquid Fertilizer ApplicationsLiquid Fertilizer ApplicationsTip # 1 - Dilute the Tip # 1 - Dilute the fertilizer with water.fertilizer with water.

Tip # 2 - Use small bilge Tip # 2 - Use small bilge pump.pump.

Tip # 3 - Pump or pour Tip # 3 - Pump or pour into prop wash.into prop wash.

Tip # 4 - Cover the Tip # 4 - Cover the entire pond.entire pond.

Water Soluble Water Soluble FertilizerFertilizer

New trend New trend

Easy to applyEasy to apply

Fast resultsFast results

Water plants Food

Excessfood

Fishes

PeptidesAmino acids

Urine

Urea

Ammonia(NH )

Algae

Nitrate (NO )

Nitrite (NO )

Feces

2

3

3

The Nitrogen Cycle

Management for N ProblemsManagement for N Problems

• Reduce DensitiesReduce Densities

• Avoid OverfeedingAvoid Overfeeding

• Water ChangesWater Changes

• AerationAeration

• SaltSalt

Clearing Muddy PondsClearing Muddy PondsStep # 1 - Find the CauseStep # 1 - Find the Cause

Undesirable SpeciesUndesirable Species

Poor Watershed ManagementPoor Watershed Management

Undesirable Water SourceUndesirable Water Source

Step # 2 - Evaluate SolutionsStep # 2 - Evaluate Solutions

Total Renovation of PopulationTotal Renovation of Population

Watershed VegetationWatershed Vegetation

Chemical AlternativesChemical Alternatives

Step # 3 - Implement Management PlanStep # 3 - Implement Management Plan

Establish vegetation in the watershedEstablish vegetation in the watershed

Lime pond, 200-500 lb Gypsum, AlumLime pond, 200-500 lb Gypsum, Alum

Phosphorus

•Limiting nutrient•Animal waste•Monitor nutrient input

>0.1 ppm (0.05 ppm)

Test Kits

• Turbidity (Secci) • DO• Ammonia• pH• Temp• Alkalinity• Hardness

Lab Analysis (UGA Extension)

• Alkalinity• Hardness• Phosphorus

1.800.ASK UGA1

More Information

http://srac.tamu.edu/

http://county.ces.uga.edu/habersham/aqua/pondmanagement.html