Backwash and Regeneration Schedule of Water Softener Tank

Someone asked about the backwash and regeneration schedule of water softener tank, every time I encounter this question, I am having a difficulty explaining the details because it is not a simple matter to discuss, we have to consider the hardness level, resin volume and volume requirement of water.

I then asked him why are you asking me and not to ask the company that installed your system? He replied to me with confidence that he was advised to do it daily. When I asked him again what is the basis of such schedule? And he said nothing.

Determining the regeneration of water softener does not require us to be an Engineer or a technical guy, it requires basic mathematics to compute as long as you know how. Even elementary student can do the computation but the problem is that, what formula are we going to use?

Here are the basic steps

1. Determine the volume of resin used, is it one bag?2 bags? etc.
2. Every bag is assumed to be regenerated at 30,000 grains (safety factor)
3. Determine the hardness level, if hardness level is expressed in PPM (Parts per million) convert it to GPG (Grains per gallon) by dividing by 17.1. If hardness level is expressed in GPG then just consider the result.
4) Divide the assumed regeneration by the hardness level expressed in GPG and you will get the volume of water that will be used prior to its regeneration.

Example

Softener tank is loaded with 1 1/2 bag of resin
Hardness level is 350 ppm

Application

1 1/2 bag resin is computed at 1.5 times 30,000= 45,000 grains
350 ppm hardness level will be divided by 17.1=20.468 GPG
Divide 45,000 by 20.468=2198.554 (volume of water to be used before regeneration)

As per the given data, we can say that we regenerate every 2198 gallons then we multiply it by 70% for the safety factor, we get 1538 gallons, this will be our reference volume every time we schedule the regeneration.

Please be noted that our reference volume does not represent the actual volume of water processed but it is the combine total of our product and reject water.

If you are using 40(product)/60(reject) ratio then you regenerate after producing 615 gal. (1538 times 40%).Always remember that this schedule of regeneration is based on the data given above and is expected to change once given data are changed.
Now that I have discussed the details, if you are on my position and someone ask you about the regeneration of water softener tank, you think you can immediately answer without getting the vital details?

If you are an existing WRS, have you been thought of these concepts? If not, it is time to look for a company that really knows what they are doing.

- Orly Shanghai