Iron coming from water softener?

[Taylorjm]

So here's what I have. My well has an iron content between 2-4ppm the two times I had it tested. For the first couple years I used big blue filters and water softener for iron removal, but then I installed a hydrogen peroxide injection system and carbon backwashing filter. So the water comes in, has the peroxide injected, goes to the pressure tank. Then to the backwashing carbon filter. Then to a 4x20 big blue 5 micron filter. This filter would originally turn bright orange right away and the clear housing (yes I know clear housings are bad) would be coated with iron residue. Then it goes to a water softener, then to another 4x20 big blue 5 micron.

So after installing the peroxide and carbon backwashing filter, the 4x20 would take a couple months to turn a little bit orange and the housing wouldn't have any orange on the plastic. Then it goes to the water softener, but the second 4x20 has big streaks of iron stains on the inside of the housing. I don't know where the iron stains are coming from but there's only maybe 10' of copper lines, then the filter after the softener, so it seems like it has to be coming from the softener. So can a softener put iron back in the water? I ran rust out on backwashing a few times in a row to try and clean it out so i'm not sure what to do now. The picture shows some of the orange streaks but it gets a lot worse right away. I attached the lab tests for untreated and after treatment. So the hardness and iron are gone. This test only showed the iron at 0.67ppm but previous lab tests were higher. The carabon backwashing filter isn't in the pictures.

 

[Bannerman]

A softener has an ability to remove some amount of ferrous (fully dissolved = clear water iron) by clinging to the resin surface.

Softening resin does not provide much sediment filtration ability, so minimal ferric iron (non dissolved = visible rust particles), will become trapped in the resin, and most will simply pass through the softener.

While hydrogen peroxide will oxidize ferrous iron to convert it to a ferric state, injecting the peroxide directly before the pressure tank and softener, provides little contact time for the peroxide to oxidize and for conversion to occur. I suspect a significant amount of conversion will be finally occurring toward the bottom of the softener, so much of the resulting ferric solids (rust particles) will exit from the softener, and will collect in the sediment filter that follows.

While you may have considered the pressure tank will provide sufficient contact time for the peroxide to act on the ferrous iron, a pressure tank holds only a relatively small amount of water while at the top of the pressure range (ie 60 psi when using 40/60 pressure switch settings), but will contain a miniscule amount of water at the bottom of the range (ie: 40 psi). When water is being consumed and after the pump becomes activated @ 40 psi, much of the flow from the pump will flow directly to the faucet/appliance where water is being utilized, thereby bypassing the pressure tank. When water use is less than the pump can supply, only the excess flow from the pump will enter the pressure tank, thereby building pressure until the pressure switch is satisfied and shuts off the pump.

While ferric iron particles will precipitate out from the water, a pressure tank provides no bottom surface for the solid particles to settle as almost all of the water within the tank will be pushed out into the plumbing system through the bottom connection anytime water is consumed while the pump is not yet operating.

 

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[Taylorjm]

A softener has an ability to remove some amount of ferrous (fully dissolved = clear water iron) by clinging to the resin surface.

Softening resin does not provide much sediment filtration ability, so minimal ferric iron (non dissolved = visible rust particles), will become trapped in the resin, and most will simply pass through the softener.

While hydrogen peroxide will oxidize ferrous iron to convert it to a ferric state, injecting the peroxide directly before the pressure tank and softener, provides little contact time for the peroxide to oxidize and for conversion to occur. I suspect a significant amount of conversion will be finally occurring toward the bottom of the softener, so much of the resulting ferric solids (rust particles) will exit from the softener, and will collect in the sediment filter that follows.

While you may have considered the pressure tank will provide sufficient contact time for the peroxide to act on the ferrous iron, a pressure tank holds only a relatively small amount of water while at the top of the pressure range (ie 60 psi when using 40/60 pressure switch settings), but will contain a miniscule amount of water at the bottom of the range (ie: 40 psi). When water is being consumed and after the pump becomes activated @ 40 psi, much of the flow from the pump will flow directly to the faucet/appliance where water is being utilized, thereby bypassing the pressure tank. When water use is less than the pump can supply, only the excess flow from the pump will enter the pressure tank, thereby building pressure until the pressure switch is satisfied and shuts off the pump.

While ferric iron particles will precipitate out from the water, a pressure tank provides no bottom surface for the solid particles to settle as almost all of the water within the tank will be pushed out into the plumbing system through the bottom connection anytime water is consumed while the pump is not yet operating.

Thanks. You may also notice the pressure tank is much larger than what most people have. It’s an 86 gallon so the drawdown is about 23 gallons. Compared to what most people have is about a 5 gallon drawdown. So only when maybe doing laundry or a shower would most of the water be consumed before the pump kicks back on. Plus it’s still holding water before the pump kicks on. Not that it’s a perfect solution but is much better than most similar setups. I will say when the carbon filter backwashes the discharge is really really orange so it’s definitely getting a majority of the iron out. But I do understand what you are saying with some precipitating out in the softener and that makes sense. I guess I’m not really sure how to I fix that except have a large holding tank, but for the issue it’s causing I doubt it’s worth it. We don’t have any noticeable iron in the toilet tanks and during the winter we may not be there to use it for a few weeks at a time. I guess my main concern was if I was doing any major damage to the softener.