2 minute pool tips: August 2011

Tuesday, August 30, 2011

Swimming Pool Filter Sizing

There is a formula for anything that you need to accomplish with regards to swimming pools, spas and hot tubs. Whether it’s a chemical adjustment or a piece of equipment that you need to replace and you want to be sure it’s the right size.

This article, as is stated in the title, is about choosing the right swimming pool filter to be sure that you’re getting the best performance and clearest pool water. Filters are one example when bigger is better!

Flow Rate / Filter Ability = Filter Size

Filter Ability for the different types of filters are as follows:

D.E. = 2 GPM per square foot

Cartridge = 0.375 GPM per square foot

Sand = 15 GPM per square foot

Ex: 75 GPM

Filter size for D.E., Cartridge and Sand would be:

75 / 2 = D.E ……. 37.5 sq ft

75 / 0.375 = Catr. …. 200 sq ft

75 / 15 = Sand …… 5 sq ft

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

Swimming Pool Spa and Hot Tub Heater Output Per Hour

This article, as stated in the title, is about choosing the right heater to bring your pool, spa or hot tub water to the desired temperature.

Formula: Heater Output:

Pool Volume (gal.) x Temp Diff. X 8.33

Ex: 20,000 gal. pool that is 77 degrees and you want to

heat it to 83. It would be; 20,000 x 6 x 8.33 = 999,600. Thiss means that you would require a 1,000,000 BTU heater to get the pool up to temp in one hour.

Note: 1 BTU = 1 lb of water raised 1 degree F.

Note: 1 gal of water = 8.34 lbs.

To find heater input: Heater Output / Heater Efficiency

Ex: Heater output = 1,000,000 BTUs

Heater Efficiency = 80%

1,000,000 / .8 = 1,250,000BTUs (Heater Input)

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

Swimming Pool Filter Ability Rate (FMR)

DIY just like a Pro!

This article, as is stated in the title, is about figuring out the rate at which water will pass through the filter media. Measured in gallons per minute per square foot (GPM/sqft)

Formula:

Flow Rate / Filter size (in sq. ft.) = Filter Ability

Ex: Flow Rate = 111GPM

Filter Size = 55.5 sq. ft.

111 / 55.5 = 2GPM Filter Ability

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

How to Calculate Swimming Pool Flow Rate

This article, as is stated in the title, is about how to calculate the flow rate of the pool water running through your system. This is an important calculation upon which many other pool formulas are based. In commercials pools and spas this is regulated by the State or Local Environmental Health Services and minimum flow rates are required.

Formula:

Pool Volume (gal) / Turnover Rate (minutes) = Flow Rate in GPM

In California (at this writing) the required turnover rates are:

Pools = 360 minutes (or 6 hours)

Spas = 30 minutes (1/2 hour)

Ex: a 40,000 gal pool would be: 40,000 / 360 = 111 GPM

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

How to Calculate Turnover Rate for Swimming Pools and Spas

This article, as is stated in the title, is about calculating turnover rates. One “turnover” is the amount of time it would take for the volume of the pool or spa water to pass through the filtration system one time. Obviously, the water is constantly mixing and, therefore, not all of the water will be filtered in the time it takes for the total volume to pass through the system but that is not important. Turnover Rate is measured in hours.

Formula:

Pool Volume (gal) / Flow Rate (GPM) / 60 = Turnover Rate (Hours)

Ex: 40,000 gal pool with a flow rate of 111 GPM would be:

40,000 / 111 / 60 = 6 hour Turnover Rate

Spa or Hot Tub Water Changing Formula

This article, as is stated in the title, is about calculating how often you should change out, or dump, your spa water. How do you know when it’s no longer worthwhile to try to improve your spa or hot tub water using chemicals? When is it better and more cost effective to simply dump the water and start over? Use this simple formula to find out if you’re fighting a losing battle.

Formula:

Spa Volume (gal) / 3 / # of users per 24 hours = Days

Example: 2,000 gal spa with 50 users over a 24 hour period.

2,000 / 3 = 666/ 50 = 13 Days

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

How to Calculate the Amount of Water (Volume) in Your Swimming Pool or Spa Square or Rectangular

This article, as is stated in the title, is about finding out how much water is in your pool or spa. You need this number for anything you want to do to or with your pool or spa. From chemical additions to turnover rates, filter rates, water changes, heating, etc.

Formula:

Length x Width x Ave. Depth x 7.48 = Volume in Gallons

Or L x W x AD x 7.48 = V

Note: 1 cubic Foot = 7.48 Gallons

Note: Average Depth is found by adding the depth at the deepest and shallowest areas of the pool then dividing by 2.

Ex: a rectangular pool measuring 18’ x 36’ with a 3’ shallow end and a 9’ deep end would be

18 x 36 x 6 x 7.48 = 29,082 gal. It is perfectly acceptable to round this number to 29,000. Anything less than 500 gallons is not going to have a huge impact on a body of water this size.

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

How to Know When to Add Chlorine to Your Pool or Spa,…and How Much

This article, as is stated in the title, is about when to add chlorine and how much you should be using. The formula we will be using is the same one that is used to calculate any chemical change in your pool or spa but we are looking at chlorine separately because it serves a different purpose in your pool than the chemicals, such as acid, do. It is used for sanitation and oxidation of organic matter.

Formula:

Amount of Chlorine (oz, lb, fl. oz, gal) x Pool Volume (gal) / 10 x Adjustment (PPM) / 1 = Total Amount needed

To get the first value, you must decide which type of chlorine you will be using and at which concentration levels.

Each has it’s own number to raise Free Chlorine (FC) by 1PPM, as follows:

Calcium Hypochlorite (Cal Hypo) 65% AC = 2.0 oz

Cal Hypo 70% AC = 1.9 oz

Cal Hypo 75% AC = 1.8 oz

Sodium Hypochlorite (Liquid Chlorine)

12% AC = 10.7 fl oz

10% AC = 12.8 fl oz

Sodium Dichloro-s-triazinetrione (Dichlor)

56% AC = 2.38 oz

62% AC = 2.15 oz

Trichloro-s-triazinetrione (Trichlor)

90% AC = 1.5 oz

Lithium Hypochlorite (Lithium Hypo)

28% AC = 4.7 oz

35% AC = 3.8 oz

Chlorine Gas

100% AC = 1.3oz

For our example, we’ll just use liquid chlorine, or bleach at an AC level of 12%. Let’s say we’re standing over our 40,000 gal pool which has a chlorine reading of 1.0 PPM and we would like that number to be a 3 PPM.

Ex: 10.7 fl oz x 4 x 2 = 85.6 fl oz of liquid chlorine would be needed.

There are times when you will need to Super-chlorinate or Shock your pool or spa water. To calculate how much chlorine you will need to reach, what is called, “Breakpoint Chlorination”, you will need to measure, both, Free and Total Available Chlorine (FAC and TAC). If these numbers are not within 0.3 of each other, you need to shock.

Formula:

Step 1. TAC – FAC = Combined Active Chlorine (CAC)

Step 2. CAC x 10 = Adjustment

Step 3. Use the Chemical Adjustment Formula

Ex: Same pool as above but the FAC = 2.0 and TAC = 4.0

4.0 – 2.0 = 2.0

2.0 x 10 = 20.0

10.7 x 4 x 20 = 856 fl oz or 6.69 gallons of chlorine. Obviously, we can just use 7 gallons.

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

Things to Know About Your Swimming Pool/Spa Filter

This article will help you better understand your filter’s ability to remove matter from your pool’s water.

The Filter type, Filter Rate, Effectiveness and Media Life of each of the 3 types of pool filters is shown below.

Filter Media- Sand & Gravel:

Filter Rate= 1.5-5 GPM/SqFt

Effectiveness: 50-100 Microns

Media Life: Top Layer = Yearly. Entire Media = 5-10 years.

Filter Media- High Rate Sand

Filter Rate= 12-20 GPM/SqFt

Effectiveness= 25 Microns (clean filter)

Media Life= Top few inches= Yearly. Entire Media = 5-10 years.

Filter Media- D.E.

Filter Rate= 1-2 GPM/SqFt

Effectiveness= 1-2 Microns

Media Life= 2 months

Filter Media- Cartridge

Filter Rate= .0375- 1.0 GPM/SqFt

Effectiveness= 15 microns

Media Life= 6-36 months

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

Swimming Pool/ Spa Water Problems, Causes, Solutions and Preventions

This article, as is stated in the title, is about the many commons problems found when maintaining a pool or spa, what may be the cause, common solutions and what you can do to prevent it happening to you again.

Problem: Cloudy Water

Possible Cause: Early algae growth, High pH, High Total

Alkalinity

Suggested Solution: See “Algae” section below, Lower

pH to 7.2-7.8, Lower Total

Alkalinity to 80-125

Preventative Maintenance: See “Algae” section below,

Maintain pH in ideal range,

Maintain Tot. Alk. in ideal

Range

Problem: Discolored Water

Possible Cause: Green/Hazy= algae, Green/Clear=

Copper or Iron,

Black/Purple/Red/Brown= Manganese

Suggested Solution: See “Algae” section below, Adjust

pH, Shock treat, Run filter,

continuously, until water is clear,

Use a metal remover followed by a

filter clean.

Preventative Maintenance: See “Algae” section below,

Maintain proper pH, Use a

sequestering agent

Problem: Algae

Possible Cause: Insufficient Chlorine

Suggested Solution: Adjust pH, Brush walls with steel

or nylon brush, shock, run filter

until water clears, clean filter. If

Yellow or Mustard algae- use an

algaecide.

Preventative Maintenance: Maintain a minimum free

chlorine reading of 1-3ppm

in all cases

Problem: Eye & Skin Irritation

Possible Cause: Improper pH, Chloramines

Suggested Solution: Adjust pH to 7.2-7.8, See “Chlorine

Odor” below

Preventative Maintenance: Maintain pH in 7.2-7.8

Range

Problem: Chlorine Odor

Possible Cause: Insufficient chlorine (The cause is,

not too much, but rather, not

enough chlorine.)

Suggested Solution: Adjust pH to 7.2-7.8, shock pool

to 10ppm of Free Chlorine (use

DPD test kit)

Preventative Maintenance: Shock treat pool weekly

or bi-weekly in the

summer.

Problem: Scale Formation

Possible Cause: High pH, High Total Alkalinity, High

Calcium Hardness

Suggested Solution: Lower pH to 7.2-7.8, Lower Tot.

Alk. to 80-120, Use sequestering

agent, Partially drain pool

Preventative Maintenance: Maintain pH at 7.2-7.8

range, Maintain T.A. at

80-120 range

(depending on type of

pool)

Problem: Corrosion of Metal Parts

Possible Cause: Low pH, Low Tot. Alk., Low Calcium

Hardness

Suggested Solution: Adjust pH to 7.2-7.8, Raise Tot.

Alk. to ideal range, Raise

Calcium Hardness to ideal range

Preventative Maintenance: Maintain pH at 7.2-7.8,

Maintain Tot. Alk. at 80

-120, Maintain Calcium

Hardness at 400-600

Ppm

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

Characteristics of Chlorine in Your Pool and Spa Water

This article, as is stated in the title, is about the strength, types, physical properties of and pH effect of the different types of chlorine used in pools and spas. Also included are the same qualities of Bromine.

% of available chlorine:

Sodium Hypochlorite = 10-12%

Calcium Hypochlorite = 65-78%

Lithium Hypochlorite = 35%

Gas Chlorine = 100%

Trichlor = 90%

Dichlor = 56-63%

BCDMH Bromine = 27%

% of active strength:

Sod. Hypo. = 10-12%

Cal. Hypo. = 65-78%

Lith. Hypo. = 29%

Gas Chl. = 100%

Trichlor = >99%

Dichlor = >99%

Bromine = 95.5%

pH in 1% solution:

Sod. Hypo. = 13

Cal Hypo = 8.5-11

Lith Hypo = 10.8

Gas = 0

Trichlor = 2.8-3.5

Dichlor = 6.5-6.8

Bromine = 4.8

pH effect in water:

Sod Hypo = Raises

Cal Hypo = Raises

Lit Hypo = Raises

Gas = Lowers

Trichlor = Lowers

Dichlor = Neutral

Bromine = Lowers

Physical Appearance:

Sod Hypo = Liquid

Cal Hypo = Granular, Tabs, Brisquet

Lit Hypo = Granular

Gas = Gas

Trichlor = Granular, Tabs

Dichlor = Granular

Bromine = Tabs, Granular

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com

Commercial Swimming Pool and Spa Bather Loads

This article, as is stated in the title, is about calculating how many swimmers/bathers are allowed in any commercial body of water at any one time. The numbers are accurate for California pools and spas as of 8/01/10 per California State Code Title 22 #65521. Using these formulas will tell you how many bathers are allowed in your particular pool or spa.

Formula:

Bather Capacity- California

Spa Pool = 10 sq. ft. per bather

Other Pools = 20 sq. ft. per bather

Bather Capacity- Non Calif. Pools

Outdoor Pools = Deep End- 27 sq. ft./bather

Shallow end (<5ft)- 15 sq. ft./bather

Indoor Pools = Total Pool Surface Are = 24 sq. ft./bather

Maximum Daily Bather Load in a 24 hr Period = 4 x bather capacity

Article by: Jef Kirchmaier, CPO, CPT, AEA, WQM

http://www.cpo2go.com