Proper pipe size for water softener and house feed?

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Rango

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Hi All,

I'm posting on this board since the project is related to replacement of my water softener system, even though the question is more general.
We're replacing our water softening system due to age. The current setup is, we are on well water. The pump outdoors runs into a closet in the garage with a pressurized holding tank. Piping from the well and into the tank is 1 inch. From the tee to the pump on/off switch is 1 inch. But after the switch, the pipe is reduced to 3/4 inch up to the softener, and the 90 degree bends look like they are only 1/2 inch inner diameter. The water softener tank has a 1 inch inlet with a 3/4 inch reducer. Coming out of the tank is also 1 inch reduced to 3/4". More 90 degrees with 1/2" I.D. And, at the cold water feed into the house, 3/4" back up to 1 inch. (There is also a similar 1cu.ft. filter tank before the softener, but that doesn't seem to be needed anymore, based on water tests and simply bypassing it the past 6 months.)

Water pressure in the house is fine with one faucet open. Low but tolerable with two open. Pressurized tank stays between upper 30's and upper 50's PSI (not quite the 40-60 setting, but close).

My questions are, if I replace the pipes with 1 inch end-to-end (tank tee, I.D. of turns, in/out water softener, to house feed), will I (1) blow out / mess up the water softener medium? (2) blow a hole in the house plumbing (mostly polybutylene unfortunately, with some copper) and overload the 50 gallon hot water heater? (3) have too much water pressure and flow, and end up requiring the pump to run too much more frequently? (4) Finally, would 3/4" pipe in the middle (as now), but with 3/4" I.D. bends, be more appropriate?

Apologies this is so long. Being an engineer, I tend to like front-loading the details.
 

Reach4

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1. No problem. The water flow during backwash is limited by the softener.
2. No. Blowouts would probably be during max pressure. If there is no flow, there is no pressure loss. Piping should be able to take more than 150 psi, and actually a lot more than that if going by typicals.

For experimenting, you might find a couple of garden hose thread gauges useful. 0-100 psi is better than 0-200. Because you don't get pressure loss with no flow, putting one on an outside hose bib or a laundry tap or two can check for drops while you fill the tub with all-hot or all-cold for a short test.
3. I don't see a problem there.
4. I suspect you are talking about 3/4 inch PEX and plastic fittings.... are you?
 

Rango

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@Reach4, thank you much for the detailed reply.

1. Part of the backwash cycle is reversing the water flow (now bottom up). Maybe no problem with just the softener medium. I was thinking what it would do to a filter tank with kdf85, carbon and a gravel bed.

4. The house was built in 1987. I really did mean polybutylene with copper fittings.
 

Reach4

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I think KDF85 is much denser than carbon. So for those to be together, you need a special arangement to reduce the diameter for the KDF vs the carbon that is seeing the same gpm backwash.

I forget what that device that holds the KDF inside of the tank is called. But I have not really studied KDF.

A 10 inch softener typically uses a 2.4 gpm backwash. A 10 inch carbon tank would be 5 or 6 gpm backwash.
 

Bannerman

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KDF85 weighs 171 lbs per cubic foot, vs softening resin @ 50 Lbs/ft3 and carbon @ 28 lbs/ft3.

Each media has unique backwash flow requirements with the recommended BW rates as follows:
Softener resin: 4-5 GPM per ft2 = 2.2 - 2.7 GPM for a 10" diameter tank
Carbon 12X40 mesh: 8-12 GPM/ft2 = 4.3 - 6.5 GPM for a 10" tank
KDF 85: 25-30 GPM/ft2 = 14-16 GPM for a 10" tank

Not recommended to combine any of those media in one tank due to the shorter useable lifespan for carbon vs the other media, and the significant variance in backwash flow requirements for each. In addition, the heavy KDF will settle to the bottom of the tank, below the resin and carbon, exactly opposite to where it will be most effective.

Without regularly backwashing at the appropriate flow rate, KDF media will not continue to remain effective, but increasing the BW flow rate to KDF requirements, will usually result in media loss as the softening resin and carbon will be slammed upward against the top of the tank and become fractured and flushed away to drain during repeated backwash cycles.

Often a small amount of KDF media will be utilized in a softener or backwashing carbon filter system, by installing the KDF within a MediaGuard which is a small diameter removable tank which is inserted and suspended within the larger tank opening directly below the control valve. The KDF within a <2.5" diameter MediaGuard, will require significantly lower BW flow than KDF within a larger diameter tank.

Although the 4-4.5 GPM recommended backwash rate for the KDF MG will continue to exceed the BW rate needed for softener resin in a 10" tank, the location for the MediaGuard will prevent resin loss.

In addition, although a smaller quantity of KDF will be contained in a MediaGuard, the MG will be located in the opening at the top of the tank where the KDF will be most effective as the water entering the tank will flow down through 4-6 separate KDF chambers to optimize contact with the KDF before becoming in contact with the carbon or softening resin below.

mediaguard-kdf-filter-for-city-or-well-water-85-55-2_1024x1024.png


mediaguard1.jpg
 
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Rango

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@Bannerman Thank you for the backwash flow numbers. We have a separate tank today for the KDF and cabon, that's in addition to the softener tank. None of our neighbors uses a pre-softener tank, and measurements the past few months with the kdf bypassed show no changes (except what I'm going to discuss next). So, I'm contemplated removing the kdf tank from the upgrade.
 

Rango

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I know this is a topic shift, but it continues the above conversation...
Our single problem now with the dual tank water filtration system (one tank holds KDF and activated carbon, the other is a salt based softener) is we get a rotten egg / sulfur smell from (some, not all) COLD water taps during WARM months. Talking to a filter company, he thinks we have biological coming into the house and sticking in the pipes. Thought is it's originating in the kdf/carbon tank which isn't backwashing enough. He recommended adding a UV light after the softener (and some bleach just before the install to kill what's currently stuck in the pipes). Water tested straight from the well only shows problems with hardness between 50 and 100ppm and TDS between 380 and 440ppm (reverse osmosis at the kitchen sink reduces that to 20ppm).

Any thoughts on the UV light or other general ones?
 

Bannerman

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with hardness between 50 and 100ppm
What test kit are you using to report hardness as ppm? The Hach 5B Total Hardness test kit is most recommended and is the most used kit by water treatment professionals & DIYs alike. The 5B accurately reports total hardness as grains per gallon.

Once of the benefits to KDF media, is a bacteriostatic effect, thereby neutralizing bacteria in the water flowing through the media. KDF85 is also effective in the treatment of hydrogen sulfide (H2S) issues, which is the cause of the rotten egg odor.

Perhaps if the KDF was backwashed at the recommended flow rate, it may then be more effective in fulfilling the purpose of why you originally chose to utilize it, in addition to the H2S and bacteria treatment benefits. You may want to consider obtaining 1 or 2 MediaGuards, to transfer at least some of the KDF you already own into each, for installation within the Carbon tank, and possibly also the softener tank.

Catalytic Carbon is often utilized for H2S issues, as it offers enhanced catalytic action compared to regular GAC (granular activated carbon). Catalytic action is required for the most effective treatment of some issues such as H2S or Chloramine removal, but, enhanced catalytic action is also a benefit of KDF85.

FYI: Advantages of KDF media for water filtration
 
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Rango

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@Bannerman Thank you for the info on KDF85. I'm planning to replace all pipes with 1". Still trying to decide whether to keep the KDF tank in addition to the softener tank. None of the surrounding neighbors use a KDF or carbon prefilter. But, the sulfur smell coming out of the taps in the summer is annoying.
 
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