Water Softeners For CH Control

[setsailsoon]

Ah, now I understand the comment. I only bring up the “sodium not salt” thing because that is the biggest misconception about them and it is often exploited by certain water conditioning companies that want to sell people very expensive fixed exchange filtration systems (“no salt” softeners). They often use the scare tactic that you’re putting salt in your water and it’s going to wreck your health if you do, etc, etc. So I’m sensitive to the “salt” comments.

So Matt, I'm back to my normal state (a little confused). Does the sodium ion poison the soil? I'm watering with 20 gr/gal super hard water as it is. Is the calcium better than sodium? Seems to me that a lot of either could be harmful but I don't have an option to eliminate them both and at least the sodium doesn't clog everything up.

Chris

PS we got the "scare tactic" sales call shortly after moving in... I kicked them out

 

[JoyfulNoise]

So Matt, I'm back to my normal state (a little confused). Does the sodium ion poison the soil? I'm watering with 20 gr/gal super hard water as it is. Is the calcium better than sodium? Seems to me that a lot of either could be harmful but I don't have an option to eliminate them both and at least the sodium doesn't clog everything up.

Chris

PS we got the "scare tactic" sales call shortly after moving in... I kicked them out

Sodium ions (Na+) are highly soluble ions that can coordinate (stick to) 6 water molecules per sodium atom based solely on Van der Waals forces. So sodium greatly affects the osmotic balance of water and ion exchange near the root system. Sodium also destabilizes clay aggregates and causes them to breakdown leaving a sandier structure to the soil.

Calcium ions don’t last long in soil before they ionically bond to carbonates forming insoluble calcite. Plants use a great deal of calcium (and magnesium) in their biochemistry and so they are a micronutrient of great value to plants. Calcium absorption also affects iron absorption in both good and bad ways. Calcium and its related compounds also affect soil pH and pH buffering capacity. Most plants thrive in soils with a pH between 6.5-7.5 and calcium can help to buffer the effects of rainfall. So calcium is actually a critical component of soil ecology. Too much is obviously not good, but it takes quite a lot of soil calcium to be detrimental.

The biggest plant offenders in municipal water is the presence of chlorine & chloramine as well as high carbonate alkalinity. Chlorine and chloramine will sanitize beneficial soil bacteria and microbes while carbonate alkalinity raises pH and locks up micronutrients like iron and phosphorous. For my sensitive plants, I keep 5 gallon buckets full of days old tap water to let the chlorine and chloramine offgas and, for pH sensitive plants, it’s not unheard of for growers to add sulfuric acid to stored water to get rid of the excess alkalinity (sulfates are not harmful to soil bacteria or plants).

 

[setsailsoon]

Sodium ions (Na+) are highly soluble ions that can coordinate (stick to) 6 water molecules per sodium atom based solely on Van der Waals forces. So sodium greatly affects the osmotic balance of water and ion exchange near the root system. Sodium also destabilizes clay aggregates and causes them to breakdown leaving a sandier structure to the soil.

Calcium ions don’t last long in soil before they ionically bond to carbonates forming insoluble calcite. Plants use a great deal of calcium (and magnesium) in their biochemistry and so they are a micronutrient of great value to plants. Calcium absorption also affects iron absorption in both good and bad ways. Calcium and its related compounds also affect soil pH and pH buffering capacity. Most plants thrive in soils with a pH between 6.5-7.5 and calcium can help to buffer the effects of rainfall. So calcium is actually a critical component of soil ecology. Too much is obviously not good, but it takes quite a lot of soil calcium to be detrimental.

The biggest plant offenders in municipal water is the presence of chlorine & chloramine as well as high carbonate alkalinity. Chlorine and chloramine will sanitize beneficial soil bacteria and microbes while carbonate alkalinity raises pH and locks up micronutrients like iron and phosphorous. For my sensitive plants, I keep 5 gallon buckets full of days old tap water to let the chlorine and chloramine offgas and, for pH sensitive plants, it’s not unheard of for growers to add sulfuric acid to stored water to get rid of the excess alkalinity (sulfates are not harmful to soil bacteria or plants).

Matt,

You always come through with the technical details that make a lot of sense. Thanks so much. My soil and water situation is way different from normal... pH is way high and barely even tolerable for Floritam. Soil is very sandy (Florida) with some rich loam. I have to add elemental sulfur to keep the pH livable. I have light brown (tan) stain in some of the over-spray areas. Was thinking about a Clack Birm bed plus resin "softener". pH is plenty high enough for the birm. Maybe I should just do the birm. If it turns out the stain is actually fine clay the birm many physically filter it anyway?

Chris

 

[JoyfulNoise]

Birm filters can be a pain and you typically need an aerator installed to increase dissolved oxygen (DO) levels. They’re not really meant to act as particulate filters so you usually want to do some sediment filtration first and then the Birm filter to remove iron followed by softening. It can get pretty complicated to remove iron.

Are you on well water?

 

[cfherrman]

Would a ta of 175 be bad for plants then?

 

[JoyfulNoise]

Would a ta of 175 be bad for plants then?

Not directly. But that is one reason why your soil pH is so high. It’s same process as in pool water - High TA means lots of dissolved CO2 can be formed which leads to pH rise as the CO2 offgasses. High pH affects plants by locking up micronutrients like iron making it harder for plants to grow. Your soil sulfur amendments help because soil bacteria oxidize sulfur into bisulfate/sulfates and that lowers pH. However, sulfur oxidation is a very slow process.

 

[setsailsoon]

Birm filters can be a pain and you typically need an aerator installed to increase dissolved oxygen (DO) levels. They’re not really meant to act as particulate filters so you usually want to do some sediment filtration first and then the Birm filter to remove iron followed by softening. It can get pretty complicated to remove iron.

Are you on well water?

I have municipal water for the house but it's still moderately hard so I installed a Fleck softener 5 years ago. Works great! Use this water for the pool also. But I have a 1/2 acre lot and it requires 15-30,000 gal of water per month (net with high-tech Rachio wifi-weather predictive control). Water is terribly expensive so everybody here uses a well for irrigation. Payout period for the well was less than a year. Birm manufacturers literature claim the unit uses DO in water so long as it's at least 25% of the iron then catalyzes the reaction to insoluble (ferrous?) iron which precipitates out in the bed then gets washed out during regen. My iron level is extremely low. 0.15 ppm ($100 lab analysis at UC Davis). As these levels I think the Birm will work. But there's another complication which is I don't really know the problem is iron. I think it could very, very fine clay. I have a filter screen on the pump discharge and it definitely collects a very small amount of the stuff. The stain is more tan to start than typical rust orange but it get's orangish with time. (maybe I hove both) The stain is completely removed with some fizzing using dilute MA. Others out here have a Rus-tec system that appears to inject a weak acid system. I'm not wild about having that in the irrigation system and having to keep filling with the "mouse-milk". If I'm right it's the particulate and it's a tiny amount and the iron could cause it to darken over time so I'm hopeful the birm may work for either. I'm sort of experimenting here with fingers crossed. What do you think? If I don't get this figured out soon the wife is gonna make me pay $35/month for Rus-tec.

 

[JoyfulNoise]

If your well water has enough DO in it, then a Birm filter will work on its own. If the DO is low and there’s not enough relative to the iron levels, then the Birm filter won’t work. It sounds like your iron levels are low enough but I’d want to know the DO number too. Air injection can be a pain to setup which is why people often opt for chlorine or permanganate injection instead.

Do you use a woven fabric cartridge filter (5 micron) at all? Sometimes just simple mechanical filtration is enough to remove iron. If there’s fine silt present, it will remove that too. You’ll want to size it appropriately though to make sure it doesn’t create too large a pressure drop.

 

[setsailsoon]

If your well water has enough DO in it, then a Birm filter will work on its own. If the DO is low and there’s not enough relative to the iron levels, then the Birm filter won’t work. It sounds like your iron levels are low enough but I’d want to know the DO number too. Air injection can be a pain to setup which is why people often opt for chlorine or permanganate injection instead.

Do you use a woven fabric cartridge filter (5 micron) at all? Sometimes just simple mechanical filtration is enough to remove iron. If there’s fine silt present, it will remove that too. You’ll want to size it appropriately though to make sure it doesn’t create too large a pressure drop.

Thanks Matt, I might try the 5 micron or 20 micron filter first. If it doesn't work it's not much lost.

Chris