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what size water softener do i need

How to Size a Water Softener to Fit Your Needs

Water softeners are sold in various sizes, symbolizing how many hardness grains they could remove before they need to regenerate.

Selecting the right size is essential because a softener that's too little will weaken its softening capacity ahead of plan, decrease water pressure and flow rate, need more time and money to

maintain, and wear out prematurely.

On the other hand, a too-large system isn't only expensive to purchase, but infrequent regeneration cycles will also damage its resin bed.

In other words, correctly sizing a water softener is crucial. How can you do that? Read the following post to find out all you will need to know.

What Size Water Softener Do I Want?

Five steps are involved in correctly sizing a water softener:

1. Finding out your water hardness level

2. Considering your daily water usage

3. Calculating your everyday softening requirement

4. Measuring your needed total grain capacity

5. Taking into consideration salt efficiency

We will discuss each step-in detail and give you loads of examples along the way, so everything is easy to understand.

When you're done reading, you can size your water softener using a reliable calculator. Then be sure you check out our water softener reviews to find the best systems on the market.

If you want to learn about all of the things to take into consideration before you buy, have a look at our water softener buying guide.

size of water softener

1. Deciding Your Water Hardness Level

Please Note: Understanding your water's precise hardness level is a must. Simply assuming will likely lead to improper sizing.

Let's begin by defining exactly what water hardness is:

Water can be "soft", "moderately hard", "difficult", etc. based on its calcium carbonate concentration. Hardness levels are measured in mg/L, ppm (parts per million), or gpg (grains per gallon). The latter is the industry standard.

How can you determine what hardness level you're dealing with? That's simple! You've got a few different options:

  • Test your water and measure calcium levels yourself. Test kits are broadly available on the internet for less than $20.
  • You can have your water tested at an independent lab (not by somebody trying to sell you anything in your living room).
  • Request a free excellent report from your regional provider (not possible if you're on a private well). Usually, past reports may also be found on the internet. Or call the company and ask.

Furthermore, you need to pay attention to elevated iron levels, especially If you get water from a well. For every one ppm of iron, then add four gpg into the total hardness value. Some specialists also suggest adding four gpg per 1 ppm of manganese.

2. Determining Your Daily Water Usage

Step two is to evaluate your household's daily water intake. If you would like to take out all of the guesswork, you should consult your most recent water bill. It will list your consumption within a specific period -- think a month, quarter, or year.

Use this number to compute the daily average.

You can do if you do not have access to the information to multiply the number of people residing in your house from 80 to 100. That is how many gallons of water that the USGS quotes an individual uses per day.

If you prefer to take long showers, then multiply by 100. If you try to conserve water as best, you can multiply by 80.

Calculation Example 1: 36,000 Gallons Usage in Q4 2018

36,000 G / 90 times = 400 gallons (daily)

Calculation Example 2: 4-Person Family, 90 Daily Gallons Per Individual

4 persons x 90 gallons/person = 360 g (daily)

3. Finding Your Daily Softening Demand

Lastly, multiply your hardness level by your everyday water usage. The result is your standard softening requirement, so how many hardness a spoonful must eliminate the water daily.

Calculation Example: Water at 20 up, 4000 Gallons Per Day

20 hardness Grains/gallon x 400 gallons/day = 8,000 hardness grains (daily)

As you can tell in the calculation example if your water measures at ten gpg and you use 360 gallons per day, then your potential new softener would have to eliminate 3,600 hardness grains daily -- so far, so good.

4. Estimating Your Expected Total Grain Capacity

Now, a water softener can only remove a lot of hardness grains until it must regenerate. This has to do with how the softening process works. Sooner or later, all resin beads within the softening tank will be saturated, indicating that they cannot bind more magnesium or calcium ions.

Regeneration involves washing out and draining off the accumulated minerals and recharging the resin bed with potassium or sodium.

Most experts recommend regenerating a softener about every six to seven days. This provides a great balance between high softening efficiency, low wastewater generation, and protecting the head valve against damage. It will also keep the resin shielding it from sediment and iron.

Multiplying our everyday softening demand of 3,600 grains by seven days, we get a total softening capacity of 25,200 grains:

3,600 Hardness grains every day x 7 days = 25,200 grains (a week)

5. Considering Salt Efficiency

Theoretically saying, this would enable us to regenerate a water purifier with a 25,200-grain score once weekly and never run short of soft water. Why theoretically saying? Because up to this point, we have not taken into account salt efficacy, a.k.a. brine efficiency.

In other words, regenerating a softener's resin bed to 100% takes a disproportionately high volume of salt. Otherwise, partial regeneration is a lot more efficient. For instance:

To fully regenerate a 33,000-grain unit, 14.1 pounds of salt are required. The identical model requires no more than 2.6 pounds of salt to regenerate 13,000 grains. And with 8.3 pounds of salt, you can regenerate 27,600 grains.

In other words, though a 33,000-grain system can eliminate 33,000 hardness grains from water within two regeneration cycles, it might demand an excessive quantity of salt doing this.

However, only recharging approx. Forty per cent of the softening bed needs less than one-fifth of the salt amount, while three-fifth of this salt would lead to about 84% regeneration. This is a much cleverer way to operate a water softener.

The higher the salt dose, the greater the burning capability, but the lower the efficiency for every pound of salt.

Bottom line: If you take a water purifier that can remove 25,200 hardness grains a week as calculated in our case above, really picking a system with a greater grain ability -- e.g., 40,000 grains -- will save you plenty of money on salt in the long term.

What's more, servicing will be more helpful, and less salt will be discharged to the environment endangering aquatic life. It will also benefit your sewer system in the event you have one.

To clarify, you will need a greater grain capacity than calculated because if you don't allow your softener to regenerate to 100%, it's going exhausted faster. A larger system can compensate for this effect.

Pound/Grains of Salt Rating

You should always check the salt efficacy of a model expressed in grains per pound of salt. The number shows how many hardness grains a spoonful can remove a pound of salt that it uses at the minimum salt dose and under real-life problems.

One model may have 4,410 @ 2.9 pounds and another one 5,060 @ 2.7 pounds. The latter is more efficient. Softeners certified with NSF/ANSI Standard 44 should have a salt efficiency rating of at least 3350 grains per pound of salt, so that is something to keep an eye out for. The efficiency for systems installed in California must be at least 4000 grains per pound.

Considering Flow Rates

Daily and weekly cutting capabilities are all good and well, but if your softener can't give enough soft water at times of peak consumption, hard water will flow through, and/, or you will find a drop in flow and pressure.

This can especially be true in the morning when everybody gets up for school and work. There could be multiple taps and showers running, toilets flushing, and possibly starting the dishwasher before leaving home.

Thus, make sure to focus on support flow rates measured in gallons per minute (GPM).

Generally speaking, bigger homes need higher flow rates. Single families might do with 7 or 6 GPM. We recommend a minimum flow rate of 12 gallons per minute for families with two or more bathrooms.

Large families should look for systems providing at least 15 gallons per minute.

Sizing Commercial Softeners

Many factors are involved in sizing a commercial water purifier. Water temperature, pressure, and flow rate are just a number of them.
However, this sizing guide is aimed at private homeowners.

We suggest that you contact a professional in your area for sophisticated commercial water softener sizing and configuration. Just know that this is not going to be cheap.

About the Author Ed Carmichael

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