Easy calculator for pool design and maintenance

ADJUSTING pH LEVEL

Current pH

pH target

Muriatic acid concentration

% ºBaume

Add ml of muriatic acid or gr of dry acid (sod. bisulfate)

Add gr of washing soda (sodium carbonate)

ADJUSTING pH -- HELP Hide

1. Do not forget to enter your pool water volume in the field Pool Size

2. Enter the measured or known pH value in the field Current pH.

3. If you use muriatic acid to lower your pool pH, first enter its concentration. Read below, in LOWERING pH how to do it

4. Enter the pH value that you want to get in field pH target and then press Enter

5. Or move the slide selector below the field to the desired pH value.

6. The CALCULATOR displays several chemical products and quantities needed to achieve the new pH

LOWERING pH

If you try to lower your pool water pH using muriatic acid, please, do first select the concentration of your acid in the field muriatic acid. The muriatic acid is diluted hydrochloric acid , its concentration is expressed in %, the calculator default value is 20%, very commonly found in the market. But you must enter the one wich you're using, you'll find it on the package label. Sometimes the concentration is expressed in degrees Baume (ºBaumé o ºBe), each ºBe is equal to 1.54%. Check options Muriatic acid concentration to be in accordance with the one indicated in the package label.

For people who prefer using a solid product to lower the pH, the CALCULATOR displays the required doses of sodium bisulfate, commonly used for this purpose

RAISING pH

If you try to reduce your pool water pH, the calculator will show the amount of pH increaser you have to add. We have selected dray acid (sodium carbonate), widely used for this purpose.

IMPORTANT NOTE

The amounts of chemical products displayed by this calculator to lower and rise the pH are purely indicative, since several factors that strongly affect the ph of the water are not taken into account, such as alkalinity, cyanuric acid, and some other parameters. The deviation can be even bigger when the difference between the current pH and the target pH becomes higher, and get bigger as we move away from values close to 7 (above and below). Therefore they shall be used as a starting point. We suggest to add the ph-Plus or pH-Minus gradually and test for the pH after each time, until we get the desired value. For more detail, click on this link (coming soon).

ADJUSTING TOTAL ALKALINITY (TA)

Current TA

ppm

TA target

ppm

Show Carbonate Alkalinity Hide

Carb. Alkalinity: ppm

Add gr of baking soda (sodium bicarbonate)

Add muriatic a. to lower TA. If pH drops to 7.0 and TA still remains high, see 'TA help'

ADJUSTING 'TOTAL ALKALINITY' (TA)---HELP Hide

1. Do not forget to enter your pool water volume in the field Pool Size

2. Enter the measured or known TA value in the field Current TA.

3. Enter the new TA value that you want to get in field TA target and then press Enter

4. Or move the slide selector below the field to the desired TA value.

5. The CALCULATOR shows how much baking soda (Sodium Bicarbonate) you have to add to achieve the new higher TA level

If you entered a new TA lower than the current TA, you try to Lower TA. Add muriatic acid to lower pH. Muriatic acid also lowers the TA. Add the muriatic acid gradually, testing pH and TA after each time. When you reach the TA target value, the process is over. But if you bring the pH down to 7.0 before bringing down the TA to the TA target value, stop adding acid and aerate the water to raise the pH to 7.2. Then add accid again and repeat the process until the TA target value is first achieved. Click here for more information (coming soon)

ADJUSTING CALCIUM HARDNESS (CH)

Current CH

ppm

CH target

ppm

Add gr of calcium chloride (anhydrous) or gr (dihydrate)

Replace m³ of the pool water by fresh water of CH ppm

ADJUSTING CALCIUM HARDNESS -- HELP Hide

1. Do not forget to enter the pool water volume in the field Pool Size

2. Test the water for calcium hardness (CH) and enter it in the field Current CH

3. Enter the CH level that you want to get in the field CH target and press Enter

4. Or move the slide selector below the field to the desired CH value.

5. The CALCULATOR shows how much calcium chloride you have to add to achieve the new higher CH level, or the volume of water you need to replace in order to achieve the new lower CH level

PLEASE NOTE:

Check carefully the form of calcium chloride in the package label. The most common is the anhydrous form and has a molar mass of 111 gr/mol, but we often come across the dehydrated form, with a molar mass of 147 gr/mol. That means you will spend 32% more in weight of the dehydrated form than when using of the anhydrous form to rise the same ppm of CH

If you have entered a value of the target calcium hardness less than the current calcium hardness, that means you like to reduce your pool CH level. Be aware that the calculator only provides the reduction of calcium hardness by draining the vessel (totally or partially) and refilling it with lower-hardness water.

Enter the calcium hardness of the fresh water available water for refilling. The field Replace displays the amount of water you have to drain and refill

ADJUSTING FREE CHLORINE LEVEL

Current FC

ppm

FC target Slider range

ppm

Using unstabilized chlorine

Add ml of bleach of or

Add gr of cal-hypo

Using trichlor (Trichloro-isocyanuric acid)

Add gr of trichlor

Cyanuric acid rise to ppm

Using dichlor (dichloro-isocyanuric acid)

Add gr of dichlor

Cyanuric acid rise to ppm

Chemicals to reduce chlorine level

Add gr of sodium thiosulfate or

Add gr of sodium bisulfite or gr of sodium metabisulfite or

Add gr of ascorbic acid or gr of hydrogen peroxide al

ADJUSTING FREE CHLORINE LEVEL -- HELP Hide

1. Do not forget to enter your pool water volume in the field 'Pool Size'

2. Test your poor free chlorine (FC) level and enter value in the field Current FC

3. If you use bleach as sanitizer, first select bleach concentration (see how below)

4. Enter the FC that you want to get in field 'FC target'

5. Or move the slide selector below the field to the desired FC value.

6. Push Enter after you finish entering data. When using slider, that is not required

7. Find below several chemical products and doses needed to achieve the new FC level

INCREASING FREE CHLORINE LEVEL

If you try to increase your pool FC level using chlorine-based bleach, please, select first the concentration of your bleach in the drop-down field after 'solution'. The chlorine-based bleach is dilute sodium hypochlorite , its concentration is expressed in % of active chlorine content. The calculator default value is the current 5% of household bleach. But a higher concentrated bleach (tipically 15% to 20% solution) is available for pool sanitation. Check your bleach container label for graduation and select it in the drop-down field

If you prefer dry non-stabilized chlorine, calcium hypochlorite (cal-hypo) is available in both granular and tablet forms. But cal-hypo rises also the water calcium hardness, so you would to check carefully it to prevent from scale-forming water because LSI becomes too high.

Dry stabilized chlorine are now commonly available for pool sanitation: trichlor (trichloroisocyanuric acid) in slow dissolving tablet form, and dichlor (trichloroisocyanuric acid) in fast-dissolving granular chlorine. Both type of chlorine put cyanuric acid (CYA) into the water and should not be used extensively to prevent the CYA level from becoming too high, making the chlorine ineffective. CYA can be removed draining part of your pool and adding water from the mains supply.

The CALCULATOR calculates and display the Cyanuric acid increments when try to you add any quantity of trichlor or dichlor. This information will help you to control your pool CYA content.

LOWERING FREE CHLORINE LEVEL

The first option to reduce the pool chlorine content is letting the pool stay with no chlorine adds and the chlorine will dissipate of its own accord in a few days The sun dries up and burns the chlorine in the water, so the levels of chlorine will automatically lower.

If you are in a hurry, for example after a chlorine shock or in indoor pools, you can force FC to lower adding a chlorine neutralizer. When you enter the calculator a target FC less than current chlorine, the CALCULATOR display how much chlorine neutralizer needs you to achieve the new lower chlorine level. Five optional neutralizers are proposed

* Sodium thiosulfate.

* Sodium bisulfite.

* Sodium metabisulfite.

* Ascorbic acid.

* Hydrogen peroxide.

Now you may choice the neutralizer compound at you convenience

ADJUSTING BROMINE (BR) LEVEL

Current BR

ppm

BR target, ppm Slider range

ppm

Using bromine tablets

Add gr of bromochloro (BCDMH) tablets

Add gr of dibromo (DBDMH) tablets

Activating the Bromide bank

Add ml of bleach solution

Add gr of cal-hypo

Add gr of MPS (Active oxigen)

Chemicals to reduce bromine level

Add gr of sodium thiosulphate

ADJUSTING BROMINE(BR) LEVEL -- HELP Hide

1. Do not forget to enter your pool water volume in the field Pool Size

2. Test your poor bromine (BR) level and enter value in the field Current BR

3. If you use bleach to activate the bromide bank, select bleach concentration

(see how in Chlorine Help)

4. Enter the bromine level that you want to get in field BR target

5. Or move the slide selector below the field to the desired BR value.

6. Push Enter after you finish entering data. When using slider, that is not required

7. Find below, in highlighted lines, several chemical products and doses needed to

achieve the new BR level

PLEASE NOTE: Once a indoor pool is treated with any kind of bromine, or a outdoor pool is treated with bromine tabs, it is always a Bromine pool until it is drained.

INCREASING BROMINE LEVEL

There are basically 2 ways to provide the pool with bromine sanitizer: in the 1-step system, the bromine is put directly into water as an ingredient in the bromine tablets. In the 2-step system, the active bromine is generated in the pool itself, by oxidation of ions of a previously established bromide ion reserve (bromide bank). The first thing is to create the bromide bank by adding enough bromide salt into the water. From then, the oxidizer agent (usually, chlorine or MPS or ozone) needs to be added on a regular basis to oxidize the bromide ions into active bromine.

The 2-step bromine systems (bromine generation in the pool)

The first step is to add bromine salt to water to set up an initial bromide reserve of not less than 30 ppm. You need to add 1.25 gr of bromine salt per each m³ of your pool to increase 1 ppm the bromide bank. That means 1,25*30*50 = 2 kg of salt bromine to for a pool of 50 cubic meters.

You can also create the bromide-bank by starting pool sanitation with bromine tablets. But, depending on several factors, it may take days or weeks until the bromine bank is properly established.

In the second step, oxidizer is supplied in a daily basis, to generate enough bromine to keep up a bromine level within 2 and 4 ppm (3 to 6 for spas). Therefore, the generated bromine is already distributed in the mass of water, and the bromine level increases immediately.

The CALCULATOR displays the amount of product needed for increasing the bromine level using 2 different oxidants at your choice:

* Liquid chlorine (bleach , sodium hypochorite)

* Dry, unstabilized chlorine (calcium hypochlorite)

Chlorine-based bleach is particularly suitable for its automatic dosing to the pool thanks to its liquid format. Just a simple dosing pump governed by a ORP controller. The automatic dosing of sodium hypochlorite or MPS is more complex due to its fast dissolving formats. If calcium hypochlorite is used as oxidizing agent, it must be taken the same precautions to prevent a excesive elevation of calcium hardness like it happens in chlorine-sanitized pools

The 2-step bromine systems (by direct addition of active bromine)

The bromine is provided by erosion of tabs of bromochloro or dibromo placed in a dispenser (brominator) or the skimmer. The CALCULATOR displays the amount in weight of both compounds required to rise the bromine level up to the desired value. But attention, both types are very slow dissolution tablets, depending on size of the dispenser it can take days or weeks until enough dissolved bromine is put into the pool.

In practice, you need to test for bromine every 2/3 days and adjust your brominator to keep bromine level within the proper range (2-4 ppm in pools, 3-6 ppm in spas) until it has settled down.

But the most convenient and effective way it to use a ORP controller with a set-point set within the range of 700 to 750 mV. The controller continuously continuously the water ORP and acts on a final control element (may be a 3-ways motor or solenoid operated valve) to adjust the time the water pass through the brominator to keep up the water ORP close to the set point.

BCDMH is a compound of chlorine and bromine. When initiating the water treatment with this compound, the two sanitizers, chlorine and bromine, coexist in the water, summing their sanitizing capabilities. Sooner or later, a sufficient reserve of bromide is generated and from then, all the chlorine is reduced to bromine All the sanitizer is already just bromine.

In a few weeks we will have a bromide bank like to that we could have created by direct addition of bromine salt. That means after a while we can switch over to the 2-steps bromine system. Simply remove or reduce the number of bromine tablets in the skimmer or brominator and start dosing with oxidant (chlorine, MPS or ozone). Of course it is perfectly possible to continue with a mixed load sharing between bromine directly provided by the tablets and bromine generated by adding chlorine, ozone or MPS.

LOWERING THE BROMINE LEVEL

The first option to reduce the pool o spa bromine content is letting the pool stay with no bromine adds. The bromine will dissipate of its own accord in a few days. The sun dries up and burns the bromine in the water, so the level of bromine will automatically lower.

If you are in a hurry, such as after a bromine shock or in indoor pools, you can force bromine to lower adding a bromine neutralizer. When you enter in the CALCULATOR a Target BR less than Current BR, the calculator display how much sodium tyosulphate needs you to meet the new lower bromine level.

The sodium thiosulphate lowers the active bromine level, but do not affects the bromide bank. Even if you add enough sodium thiosulphate to cut to 0 ppm the bromine content, your pool / spa continue to be bromine sanitized until the bromide level gets below a few ppm.

PUMP SIZING

Pool Turnover time Pump flow

hr m³/hr

PUMP SIZING -- HELP Hide

Turnover time is the time (in hours) required by the pump to circulate through the filter a volume of water equal to the pool capacity. The more powerful the pump, the higher the flow that recirculates and therefore lower turnover time, but both pump and filter become bigger and much more expensive. A balanced approach to ensure clean, clear water is accomplished with turnover time between 2.5 and 6 hr, depending on the pool size.

Steps to calculate the pump flow to achieve the desired turnover time:

1. Do not forget to fill in the field 'Pool size' in 'My Pool'

2. Enter the desired turnover value in the field 'Pool Turnover time'.

3. Or move the slide selector below the field to the desired turnover value.

4. Press Enter after you finish entering data. When using the slider, that is not required

The pump flow to achieve the desired turnover time is shown in the field 'Pump flow'

You can also directly enter the desired pump flow in the field 'Pump flow", then press Enter and check that the turnover time value shown in the field 'Turnover time' is within the correct range.

FILTER SIZING

Filter type:

-Sand
-Zeolite

Filter flow rate Filter diameter

m³/hr/m² mm

Filter type:

-Cartridge
-Diatomite(DE)

Filter flow rate Filter area

m³/hr/m² m²

FILTER SIZING -- HELP Hide

The filter must be sized to match the pump. Filter flow rate is the velocity that water moves through the filter and depend on filter area. The slower the flow rate, the better the quality of filtration. If the filter is undersized (area too low=flow rate too high) filtration quality is poor and it becomes clogged very soon. But if the filter is oversized (area too high=flow rate too low) the pump flow available is not sufficient for a good filter back-washing.

The general rule of thumb for filter rate margin is:

* Sand filter: 37-50 m³/hr/m² (15-20 GPM/FT2).

* Zeolite filter: 30-40 m³/hr/m² (15-20 GPM/FT2)

* Diatomite filter (DE): maximum 5 m³/hr/m².

* Cartridge filter: maximum 2.5 m³/hr/m².

Once we select the flow rate, the filter diameter is calculated and displayed for sand and zeolite filter. For cartridge and DE, the filter area is calculated and shown since that is the applicable criteria of selection for these types of filters.

How to select the correct SAND or ZEOLITE filter for your pool

1a. First select the right pump in panel 'Pump selection'. The pump flow is then used as input for the filter calculations.

2a. Then go below to the panel FILTER SIZING, sand and zeolite type.

3a. The CALCULATOR assumes by default a sand filter based on a filter flow rate of 40 m³/hr/m² and shows its size in the field 'Filter diameter'. If you prefer a bigger or smaller sand filter, or your filter is a zeolite filter, go to next step 4a.

4a. Enter in the field 'Filter flow rate' the desired value and press the Enter key, or move the Filter flow rate slider selector to the desired value within the slider scale. Please, check that selected 'Filter flow rate' is within the proper range depending on filter type, sand or zeolite type. The filter size is then shown in the field 'Filter Diameter'.

5a. You can also directly enter the desired filter diameter in the field 'Diameter filter', press the Enter key and you read in the field 'Filter flow rate' the flow rate to the new filter size entered. Be careful that the filter flow rate is within the right range for your sand or zeolite filter type

How to select the correct DE or CARTRIDGE filter for your pool

1b. First select the right pump in panel 'Pump selection'. The pump flow is then used as an input for the filter calculations.

2b. Then go below to the panel FILTER SIZING, diatomite and cartridge type.

3b. The CALCULATOR assumes by default a Diatomite filter based on a filter flow rate of 4 m³/hr/m² and shows its size in the field 'Filter area', 0,62 m². If you prefer a bigger or smaller DE filter, or your filter is cartridge type, go to next step 4b.

4b. Enter in the field 'Filter flow rate' the desired value and press the Enter key, or move the Filter flow rate slider selector to the desired value within the slider scale. Please, check that selected 'Filter flow rate' is within the proper range depending on filter type, DE or cartridge type. The filter size is then shown in the field 'Filter area'.

5b. You can also directly enter the desired filter area in the field 'Filter area', press the Enter key and you read in field 'Filter flow rate' the flow rate for the new filter area entered. Be careful that the filter flow rate is within the right range for your DE or cartridge type

Pool and spa piping system calculations. Coming soon

Cálculo de tuberías de piscinas y spas. Próximamente