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Digital Field Reference
Pool Service Techs
Pool Acid Dose Calculator
About This App
This pH calculator tells you the exact amount of acid needed in any pool or spa to lower pH or total alkalinity. It tells you how to lower pH in pool water.
Enter pool volume in gallons or liters, current pH, current alkalinity and desired pH and it calculates the amount of acid needed for three kinds of acid in metric or US units of measure and calculates the new alkalinity after adding the acid dose. It even considers the effects of CYA (cyanuric acid) and borate if they are used.
This is the first pool calculator of its kind. Now you don’t need to guess at the amount of acid or what it will do to the pH and alkalinity in your pool or spa after you add it. It will tell you how to lower pH in pool water. You don’t need an Acid Demand test any longer. Plug in the desired pH you want and you get the amount of acid and the new alkalinity.
Want a specific alkalinity?
Input different desired pH values until you reach the alkalinity you want. Want to know what will happen if you add a specific amount of acid? Just keep changing the desired pH until the amount of acid is near the amount you want to know about. It’s easy. It’s accurate and it save time and money.
Pool Water Saturation Index
About This App
The NPC LSI Calc is the newest, most advanced and most accurate pool calculator for determining the Langelier Saturation Index (LSI) for swimming pool and spa water.
It was developed by noted pool and spa water chemistry expert and author, Robert W. Lowry. It is the only LSI calculator that currently has exact adjustments for cyanuric acid and borate.
The LSI is used to predict if pool or spa water is corrosive, balanced or scaling. The NPC LSI Calc uses the original mathematical equations which use logarithms, square roots, and interpolated constants for calculations. We do not use inaccurate lookup tables and factors. The actual water test results are used for calculations.
The NPC LSI Calc is easy to use, you input the customer or pool name and then the water test results for pH, Total Alkalinity (TA), Cyanuric Acid (CYA) Borate (B) Calcium Hardness (CH), Total Dissolved Solids (TDS), and the water Temperature (T) in degrees Fahrenheit. The LSI with adjustments is automatically calculated and displayed. The background color of the LSI value changes from green to amber to red depending on whether the water is Corrosive, Acceptable, Ideal, or Scaling. This gives a visual or at a glance notice of the water’s condition.
The original LSI was never intended for predicting corrosive, balanced or scaling water conditions for pools or spas. In fact, it was developed in 1936 which was many years before the development of Cyanuric Acid (CYA) which became popular around 1960 and remains so. The very popular trichlor chlorine tablets actually contain 56 % CYA and so as chlorine is dispensed, the CYA builds up in the water. CYA has a direct influence on Total Alkalinity (TA) so an adjustment had to be made to the original LSI calculation.
Another family of chemicals that have become popular recently as a pH buffer and algaestat in swimming pool and spa water are borates. Borates also have an influence of TA. Using borates in pool or spa water keeps the pH from rising but also requires an adjustment to TA and therefore has an effect on the LSI calculation too.
We have determined the exact affect borate and CYA will have on LSI calculations and built in the mathematical adjustments to the NPC LSI Calc App.
The goal mathematically is to have an LSI of near 0.00 but any value from –0.30 to + 0.50 is either Acceptable or Ideal. Positive values show increasing tendencies for forming scale and values more than +0.50 indicate scaling water conditions that require action. Negative values show increasing tendencies for being corrosive or aggressive and values greater than –0.30 indicate corrosive water that requires action.
We do not recommend which water conditions to change or chemical amounts to adjust the water balance or LSI. Which condition to adjust is best accomplished by the service tech, pool owner or pool store. There may be reasons that one condition or another cannot be changed or perhaps a condition is easier to change than another. But you can input new amounts for any condition to see what affect it will have on LSI.
Results can be saved and reviewed. The number of records saved is only limited by your phone’s memory. It is easy to delete of records.
Pool Chemical Dose Calculator
About This App
Pool Chem Dose Calculator is a pool calculator that will calculate the exact chemical dose needed for 38 chemicals in 11 categories for any size pool in US Imperial or Metric measures.
To use it you enter the pool volume in gallons or liters, choose US Imperial or Metric, select which item you want to change from the drop down list and then enter the desired change in ppm or mg/l. Pool Chem Dose Calculator then lists all of the chemicals that can be used for that item change and the doses for each one.
NOTE: The qts for Liquid Chlorine and Liquid Bleach are incorrect. The correct amount is half of the amount listed. Please divide the listed amount by 2.
Pool Chem Dose Calculator is a pool calculator that will calculate the exact chemical dose needed for 38 chemicals in 11 categories for any size pool in US Imperial or Metric measures. To use it you enter the pool volume in gallons or liters, choose US Imperial or Metric, select which item you want to change from the drop down list and then enter the desired change in ppm or mg/l. Pool Chem Dose Calculator then lists all of the chemicals that can be used for that item change and the doses for each one.
No brand names, no sales just the exact dose of the chemical you want to use by chemical name. Use it to find out how much chemical to add to make a correction or increase or decrease a condition.
For example, if you want to Increase Chlorine by 3 ppm in a 14,750 gallon pool, enter 14750, select US Imperial, select Increase Chlorine from the drop down menu and enter 3.0 in ppm. Instantly see the amounts needed to get 3.0 ppm chlorine in that pool for 15 types of chlorine. Makes it easy to compare and see which might be cheaper to use or make a substitution.
You can also use the Pool Chem Dose Calculator to figure out the change to a water condition if you add an amount of chemical. For instance suppose you have a 15,000 gallon pool and you want to know how much the free chlorine will increase if you add a gallon of 10% liquid chlorine. No problem, just enter the pool volume, select US Imperial, select Increase Chlorine and then enter an amount for ppm. Keep changing the ppm up or down until the dose amount for Chlorine 10% gets near 128 fl oz or 4 qts.
Pool Drain Percent Calculator
About This App
The Pool Drain Percent Calculator is used to determine the percent or fraction of water to be drained to reach a Target for a specific condition in the water.
The problem is this. A condition in the pool is too high and you need to drain some water. However, the make up or source water also has some level or concentration of that condition in it. How do you figure out how much to drain from the pool and end up with the desired Target?
Using the Pool Drain Percent Calculator, you enter the condition in the pool water, then enter the Target or Desired level in the water and finally, enter the level or concentration of the condition in the source or make up water.
Pool has 600 ppm Calcium Hardness. Target for Calcium Hardness in the pool water is 350 ppm. Source or make up water has 150 ppm calcium hardness.
In cell Condition in Pool enter 600
In cell Target Condition enter 350
In cell Condition in Source enter 150
Read Drain 55% in Amount to Drain. This is the percentage of the average depth that should be drained and refilled with source water to achieve the Target of 350 ppm calcium hardness.
Pool has 420 ppm CYA (cyanuric acid). Target for CYA in pool water is 50 ppm. Source or make up water has 0 (zero) CYA.
In cell Condition in Pool enter 420
In cell Target Condition enter 50
In cell Condition in Source enter 0
Read Drain 88% in Amount to Drain. This is the percentage of the average depth that should be drained and refilled with source water to achieve the Target of 50 ppm CYA.
Pool Borate StartUp Calculator
About This App
The Borate Pool Start Up Calculator was developed by expert chemist, Robert Lowry primarily for professional service technicians for starting up a new plaster, quartz, exposed aggregate, pebble, or cementitious pool surface, but can be used for any pool surface including vinyl, fiberglass, acrylic, polyethylene, or stainless steel.
The Borate Pool Startup Calculator is a step-by-step, 7-day procedure for starting up a new pool or a recently remodeled pool that calculates a chemical dose for each of the steps for each day based on water pool volume, water tests made each day before chemicals are added and compared to Target values. Exact chemical doses are given. It also provides a record of all chemicals used, amounts added, the order of addition, and date of completion for future reference.
A comprehensive list of information called Getting Ready begins the process of Start Up. It has suggestions, preparation and pool filling recommendations, and other tips.
Source water is tested before beginning and results entered into the app. Recommendations are made for metal removal, using a pre-filter, a metal removal bag, or a sequestering agent.
Each day begins with water testing and recording results in the app. The Borate Pool Start Up Calculator then analyzes those results and prescribes an exact amount of each chemical to be added for that day, step by step. It also has reminders that the surface should be brushed twice each day. The critical part of the start up is complete with Day 3.
Borate is added on Day 1 to help prevent the pH from going very high and to prevent algae but not kill it (algaestat). Borate remains in the water helping to prevent the pH from going up and keeping algae from getting started.
Calcium level: Day 1, check calcium, and make sure it is at least 150 ppm, add calcium increaser if necessary. On Day 2, calcium hardness is increased to 200 ppm unless it is already above 200 ppm. Day 3, calcium hardness is increased to 250 ppm.
CYA and chlorine are added on Day 3.
Service techs and others using the Borate Pool Start Up Calculator open the record for that customer for that Day to continue the process until completed. Days 4-7 has user input for water conditions and calculates the Langelier Saturation Index for those test results. The app does not make recommendations for chemical additions on days 4 through 7. The critical part of Borate Pool Start Up is complete with the end of Day 3. Days 4-7 should only require minor adjustments to pH, alkalinity, and free chlorine which can best be accomplished using the Pool Acid Dose Calc or the Pool Chemical Dose Calculator. When the Steps are completed and the information for Days 4-7 has been entered, records are saved to the phone or device memory. Records can be searched for by date, customer name, or service tech and reviewed. Records can also be downloaded or emailed.
Days 8-28 are on one screen
Targets are given for all water conditions or parameters.