Unit Conversion Tables

 

Useful Conversion Factors

LENGTH

IN

FT

YD

M

INCH (IN)

1

0.833

0.0278

0.0254

FOOT (FT)

12

1

0.333

0.305

YARD (YD)

36

3

1

0.9144

METER (M)

39.37

3.281

1.094

1

AREA

IN²

FT²

YD²

SQUARE INCH (IN²)

1

0.00624

0.000772

0.000645

SQUARE FOOT (FT²)

144

1

0.111

0.0929

SQUARE YARD (YD²)

1296

9

1

0.836

SQUARE METER (M²)

1550

10.76

1.196

1

VOLUME

US GAL

IMP GAL

FT³

US GALLON (US GAL)

1

0.833

0.134

0.0038

IMPERIAL GALLON (IMP GAL)

1.2

1

0.161

0.0045

CUBIC FOOT (FT³)

7.481

6.229

1

0.0283

CUBIC METER (M³)

264.172

219.97

35.3147

1

VELOCITY

FT/S

FT/M

M/S

 

FOOT/SECOND (FT/S)

1

60

0.305

 

FOOT/MINUTE (FT/M)

60

1

18.288

 

METER/SECOND (M/S)

3.281

196.86

1

 

FLOW

US GPM

IMP GPM

M³/H

L/S

US GAL/MIN (US GPM)

1

1.201

0.273

0.076

IMP. GAL/MIN (IMP GPM)

0.833

1

0.227

0.063

M³/HOUR (M³/H)

3.667

4.403

1

0.278

LITRE/SECOND (L/S)

13.198

15.85

3.6

1

FILTRATION VELOCITY

US GAL FT²/MIN

IMP. GAL/FT²/MIN

FT³/FT²/MIN

M³/M²/HR

US GAL/ FT²/MIN

1

0.833

7.45

0.134

IMP. GAL per FT²/MIN

1.201

1

0.158

2.936

FT³/FT²/MIN

7.474

6.311

1

18.322

M³/M²/HOUR

0.409

0.341

0.055

1

MASS

Lb

Kg

g

 

POUNDS (Lb)

1

0.454

454

 

KILOGRAM (Kg)

2.205

1

1000

 

GRAM (g)

0.0022

1000

1

 

PRESSURE

PSI

BAR

Kg/cm²

PA

POUND²/INCH (PSI)

1

0.07

0.07

6895

BAR

14.5

1

1.02

100,000

Kg/CENTIMETER² (Kg/cm²)

14.23

0.98

1

98,100

GPASCAL (PA)

0.00014

0.00001

0.00001

1

ENERGY

J

KWH

KCAL

BTU

JOULE (J)

1

0.000000277

0.00024

0.0095

KILOWATT/HOUR (KWH)

3,600,000

1

861.244

3412.14

KILOCALORIE (KCAL)

4186

0.0012

1

3967.44

BRITISH THERMAL UNIT (BTU)

1055.06

0.00029

0.252

1

POWER

KW

HP

BTU/HR

 

KILOWATT (KW)

1

1.341

3412.14

 

HORSEPOWER (HP)

0.746

1

2544.43

 

BTU/HOUR  (BTU/HR)

0.00029

0.00039

1

 

TEMPERATURE

°C

°F

K

 

CELSIUS (°C)

1

1.8°C+32

°C+273.16

 

FAHRENHEIT (°F)

(°F-32)/1.8

1

n/a

 

KELVIN (K)

K-273

n/a

1

 

 

 

 

 

 

We supply all plant and equipment featured on this website. All our work is Guaranteed; Parts and Labour

For free and unbiased advice, a site visit or no-obligation Quotation*, please make initial enquiries by email. Tell us a little about your pool problem and include a daytime phone number. Thanks, we look forward to meeting you soon

Note: - Please contact our recommended pool professionals for supply and installation of all pool-related services: - 

Costa del Sol - This email address is being protected from spambots. You need JavaScript enabled to view it.

Nerja area - This email address is being protected from spambots. You need JavaScript enabled to view it.

*We only offer Quotations: - a fixed, agreed price that cannot, and will not, be increased. We do not give 'estimates', as an estimate offers the client no guarantee of final price

Share this website with other Pool Owners and Users,  encourage them to read about Pool Safety, learn CPR and help them to save lives, time and money. Please help us to make every pool a safer place - by sharing this information we can cut the number of pool accidents and deaths.  Please also see our FacebookFacebook page

Ken Walker - MyPoolGuru©

In-ground Pump and Filter

Filtration

 

 - here are the correct valve and switch positions 

for pools cleaned via the Vacuum Socket Method

  • ‘Skimmer’ and ‘Jets’ Valves fully open
  • 'Bottom Drain Valve half open
  • ‘Waste’ and 'Vacuum' Valves closed
  • Timer running and set for 4 hours in every 12 hours
  • Always have the pump/filter running when the pool is in use

 

And here they are for pools cleaned by the Skimmer Socket Method

 

  • ‘Skimmer’ and ‘Jets’ Valves fully open
  • Bottom Drain Valve half open
  • ‘Waste’ Valve closed
  • Timer running and set for 4 hours in every 12 hours
  • Always have the pump/filter running when the pool is in use

 

We supply all plant and equipment featured on this website. All our work is Guaranteed; Parts and Labour

For free and unbiased advice, a site visit or no-obligation Quotation*, please make initial enquiries by email. Tell us a little about your pool problem and include a daytime phone number. Thanks, we look forward to meeting you soon

Note: - Please contact our recommended pool professionals for supply and installation of all pool-related services: - 

Costa del Sol - This email address is being protected from spambots. You need JavaScript enabled to view it.

Nerja area - This email address is being protected from spambots. You need JavaScript enabled to view it.

*We only offer Quotations: - a fixed, agreed price that cannot, and will not, be increased. We do not give 'estimates', as an estimate offers the client no guarantee of final price

Share this website with other Pool Owners and Users,  encourage them to read about Pool Safety, learn CPR and help them to save lives, time and money. Please help us to make every pool a safer place - by sharing this information we can cut the number of pool accidents and deaths.  Please also see our FacebookFacebook page

Ken Walker - MyPoolGuru©

Algae

Algae are microscopic single-cell plants that can enter the water from the atmosphere by the actions of wind and rain. There are over 30,000 different varieties of algae

The three main categories are: -

Green Algae

- usually free-floating although they sometimes colonise surfaces

The green algae are the fastest growing algae and are responsible for most 24-hour algae blooms

When pool water becomes turbid (cloudy) with algae it makes the pool dangerous to use, as it is difficult to see the bottom of the pool

As the water turns green the surfaces of the pool develop a slippery feel.  The water becomes hazy, pH will shoot up and chlorine levels will drop sharply

A bloom of green algae can turn a clear, clean pool into a green swamp overnight

The pH rises as algae consume the carbon dioxide (CO2 helps to keep the pH down), and the pool surfaces will be coated with a slippery Bio-film

Once algae become visible you’re in trouble.  Algae take in carbon dioxide and give off oxygen like most other plants

Most bacteria found in swimming pools take in oxygen and give off carbon dioxide

Each grows by consuming the by-products of the other, and thus the proliferation of both organisms accelerates

For this reason we use a chemical program that assures both bacterial and algae control

Mustard (Yellow) Algae

often appears on the shady side of the pool as a yellow powdery deposit.  Once established, yellow algae are Chlorine resistant and can survive in the presence of 3-5 ppm of free chlorine.  Superchlorination will kill mustard algae but the dead cells must be scrubbed from surfaces

Black (Blue-Green) Algae

evident by the formation of 1 to 3cm sized black (or dark blue-green) spots on the pool surfaces, especially on the grout lines or plaster.  Black algae form a layered structure where the first layer (which superchlorination may kill) protects under-layers from further destruction

Black algae are similar to the algae that are found on bathroom shower tiles and in silicone seams near the bath. This form of algae is very slow growing but very hardy; it is extremely Chlorine resistant

Black algae can be controlled by the use of Copper Sulphate or a Copper Ioniser

Prevention of algae

A successful program of regular pool maintenance prevents algae from growing. This is achieved by monitoring and controlling pH and residual free chlorine in the water

Application of a general Algaecide or Algaestat is also recommended.  Use Copper Sulphate at a rate of 3 grams per cubic m3. This chemical should not be applied more than 2 times per season to avoid overdosing, which can cause blue staining of the plaster or grout, green hair and blue nails

We supply all plant and equipment featured on this website

All our work is Guaranteed; Parts and Labour

For free and unbiased advice, a site visit or no-obligation Quotation*, please make initial enquiries by email. Tell us a little about your pool problem and include a daytime phone number. Thanks, we look forward to meeting you soon

*We only offer Quotations: - a fixed, agreed price that cannot, and will not, be increased. We do not give 'estimates', as an estimate offers no guarantee of final price.

 

Note: - Please contact our recommended Pool Professionals for supply and installation of all pool-related services: - 

All Spain and Portugal - PoolSafetySpainPoolSafetySpain - for supply and installation of Pool Safety Equipment

Costa del Sol - PoolSchool S. L.PoolSchool S. L. - Pool Services, Solar heating, Spas, 

Nerja area - PoolTechNerjaPoolTechNerja - as above

Each of the above offers years of experience, free unbiased advice and excellent, Professional service.

Share this website with other Pool Owners and Users, and help us to make every pool a safer place. By sharing this information we can cut the number of pool accidents and deaths.  Please also see our FacebookFacebook page

Ken Walker - MyPoolGuru©

 

brown water from tap

Water Problems

- when you think about it, keeping fifty tons or more of exposed-to-the-elements water in crystal clear condition is no easy task

Any pool is constantly under assault from algae and fungi spores, garden debris, rain, sun, wildlife, pets, building/quarry/road dust and a host of other pollutants

That's before any humans get into the water and add their share of sun-oils, hair, dead skin, mucus, body fats, sweat, faecal matter and urine - (yes, I'm afraid people still do), never mind the effect the Labrador and the local wildlife can have on your pristine pool

When pools go bad they can do it very quickly. After a summer storm your pool can take on the appearance of a murky, green swamp overnight. Not a pretty sight in the morning and an expensive mess to sort out

The pool-owner is left to clean the mess up, or leave it to his pool cleaner and, at the end of it all, pay the bill or -  you could learn how to clean and maintain your pool by following the advice on this site . . . 

Unfortunately, accurate diagnosis of pool water problems is not always straightforward. It’s often a case of considering the possibilities and identifying the most likely cause from other evidence; e.g., Test kit results and/or the appearance of the water, the pool surfaces and other factors

Read the possible causes for each symptom and pick the most likely suspect - if that doesn’t solve the problem; try the next most likely

Cloudy/Milky Water

There are four possibilities - your test kit will help you to decide which the culprit is

1st possibility - suspended particles give a milky white discolouration

This is likely to be caused by precipitation of dissolved minerals as a result of high pH

Cure: - Reduce the pH

To lower pH by 0.2 add Hydrochloric Acid at a rate of 1 litre per 50 m³ (13,000 US Gallons) of pool water

Run the pump for 4 hours after dosing then test again

Repeat until correct reading is reached

2nd possibility - dirt or bather pollution build up due to low chlorine or poor filtration

Cure: - clean the filter, Superchlorinate to 10ppm and then apply a Flocculant

3rd possibility - the levels of stabiliser (Cyanuric Acid) are too high. The Chlorine takes longer to kill organisms, which can then proliferate and lead to haziness in the water

Cure: - Replace some of the pool water by draining to waste (or carry out an extra-long backwash), top up with fresh water, then Superchlorinate to 10ppm

4th possibility - ineffective filtration

Cure: - Check the filter media and replace if necessary

Change the filter contents every 4 years (every 7 years if using Zeolite)

Cloudy, green  water

Cause - low chlorine levels or ineffective chlorine have allowed green algae to flourish

Cure: - Superchlorinate to 10ppm (25ppm for more serious problems) and leave the pump running for 24 hours to kill the algae

Brush all surfaces to dislodge algae and to improve the circulation of the superchlorinated water

Clean the filter after 24 hours

Any water haze can be removed with flocculant or Jolly Gel

If your pool is susceptible to algae use an algaecide monthly

Rust-stained Water

Caused by: - The corrosion of ferrous parts of the circulation system by low pH water

Cure: - Act swiftly to prevent further damage - such as staining of the plaster, grout or liner

Check with your Pool Shop to see if it is safe to empty the pool and replace the water all in one go, or if should be done by progressive dilution

Remove rust stains from the pool surfaces with a proprietary tile or liner cleaner

Use PVC fittings to replace the ferrous metal fittings

Balance the fresh water as you refill your pool

Chlorine Level Problems

Chlorine has been added, but there is no reading on the test kit

Possible cause 1 -

Old, inaccurate or ineffective Test kit. Remember to buy a new kit every year - they are inexpensive and are your key to understanding what is happening in your pool

Possible cause 2 - The Chlorine level may be so high that it bleaches the colour in the test kit, or exceeds the range of a Photometric Meter, although both of these are unlikely

To check this diagnosis see if you can smell Chlorine at the surface of the water, or repeat the test with only a droplet of pool water, diluted with tap water,  in the test tube and watch closely to see if there is a discolouration before the bleaching occurs

Cure: - Determine the approximate level of Chlorine by diluting the sample of pool water with an equal quantity of natural or distilled water; multiply the answer by 2

If there is still no reading, dilute the water sample with 3 parts of water; then multiply the answer by 4...and so on

Alternatively you can have a sample of your pool-water tested at most pharmacies and pool-shops

If the actual Chlorine reading is under 10ppm, suspend dosing until it drops over a period of time

If the Chlorine reading is higher than 10 ppm, reduce the free Chlorine by adding Sodium Thiosulphate

WARNING:  dose with Sodium Thiosulphate at 250g per 50m³ (13,000 US Gallons)

Apply in several small additions; wait 4 hours with the pump running and test Chlorine levels after each dose

Overdosing with Sodium Thiosulphate could leave you with a Chlorine deficit for weeks

Chlorine level is difficult to maintain

1st possibility - The free Chlorine is being decomposed by UV from the sun’s rays

Cure: - If you are using Sodium Hypochlorite or Calcium Hypochlorite, add stabilizer (Cyanuric acid) at a rate of 500 grams per 50m³ (13,000 US Gallons) - his should be dosed directly into the pool at the jets with the pump running

Alternatively, change to a stabilised Chlorine such as Trichlor 

2nd possibility - High water temperature

Cure: - Increase the dose rate of Chlorine proportionately as the temperature rises

Keep a close eye on Chlorine levels in hot weather

Once the water temperature goes above 26 °C, the Chlorine demand will roughly double for every 5 °C

3rd possibility - A build-up of pollutants due to low Chlorine, causing an increased Chlorine demand

Cure: - Superchlorinate to 10ppm

4th possibility - incorrect level of Total Alkalinity (TA)

Cure: - TA is a measure of the bicarbonates that are dissolved in the water

TA is important because if it’s to low you will get ‘pH Bounce’ and if it’s too high you’ll have great difficulty in changing the pH value

Take a sample of your pool water to your local pool-shop or pharmacy

They will test the water, for a reasonable fee, and tell you the TA level of your pool water and any other information you need

Increase TA by adding dissolved Sodium Bicarbonate with the pump on

Reduce TA by adding pre-dissolved dry acid or Hydrochloric (Muriatic) Acid to the deepest part of the pool with the pump off

Check the container instruction for quantities

pH Problems

pH remains too low

Likely cause - This is usually due either to low pH of mains water (soft water areas), incorrect TA levels or to the use of low pH (acidic) Chlorine donors

Cure: -adjust TA as required

Correct the pH by adding pH-Plus powder

You might also consider changing to a high pH Chlorine donor to help to counteract the low pH of the fill-water

Dichlor is roughly pH neutral; Tricloro is low pH (acidic), while Calcium Hypochlorite and Sodium Hypochlorite are both high pH (alkaline) Chlorine donors

pH is permanently too high

Likely causes: -

(1) High pH of mains water (hard water areas) or

(2) Regular use of alkaline Chlorine donors such as Calcium Hypochlorite or Sodium Hypochlorite, or

(3) Hardness salts being leached from new concrete or mosaic pools

Cure: - in all of the above cases the solution is the same; correct the pH

For (1) and (2), consider a change to a low pH Chlorine source such as Trichlor to help achieve a balance between the high pH of the water and the low pH of the Chlorine donor

As for (3) - the difficulties with new pools will eventually clear up on their own accord over time

pH values are erratic and fluctuate

Likely cause - The Total Alkalinity is too low to buffer the pH

Cure: - Add Sodium Bicarbonate to raise Total Alkalinity to 80-120 ppm

Dose at 1.5kg per 50m³ (13,000 US Gallons) of pool water; pre-dissolve and distribute around the pool with the pump on

pH is locked

Likely cause - The water is over buffered due to high Total Alkalinity (TA) - this is a common problem in hard water areas

Cure: - Add dry acid (Sodium Bisulphate) to lower the TA to 80-120 ppm

The dose rate is 1kg per 50m³ of pool water or 13,000 US Gals

Add the acid, a little at a time and pre-dissolved at a dilution of 10:1, to the deepest part of the pool with the pump turned off

Leave the pump off for 24 hours, then run the pump for 4 hours, re-test and repeat as required

Note: It may take weeks of patient treatment to reduce TA to acceptable levels

 

We supply all plant and equipment featured on this website. All our work is Guaranteed; Parts and Labour

For free and unbiased advice, a site visit or no-obligation Quotation*, please make initial enquiries by email. Tell us a little about your pool problem and include a daytime phone number. Thanks, we look forward to meeting you soon

Note: - Please contact our recommended pool professionals for supply and installation of all pool-related services: - 

Costa del Sol - This email address is being protected from spambots. You need JavaScript enabled to view it.

Nerja area - This email address is being protected from spambots. You need JavaScript enabled to view it.

*We only offer Quotations: - a fixed, agreed price that cannot, and will not, be increased. We do not give 'estimates', as an estimate offers the client no guarantee of final price

Share this website with other Pool Owners and Users,  encourage them to read about Pool Safety, learn CPR and help them to save lives, time and money. Please help us to make every pool a safer place - by sharing this information we can cut the number of pool accidents and deaths.  Please also see our FacebookFacebook page

Ken Walker - MyPoolGuru©