Chlorine injection system, but no chlorine detected

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jrsummersill1

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We just bought and installed a used chlorine injection system. The previous owner told us that in the chlorine tank they always used 2gallons of chlorine to about 18 gallons of water. We have had it installed for about a week now and the chlorine tank has been going down, but we cannot detect any chlorine whatsoever in the water. We even took a sample to our local pool supply store and they did not detect the presence of any chlorine either. We know that the chlorine is being injected as when the well pump comes on and the injection pump comes on, we see the chlorine line pulsating. Yesterday we even added an additional 2.5 gallons of chlorine, making it approximately 4.5 gallons, and still cannot detect any chlorine! We have a 5 hp well pump that pumps about 30 gallons per minute and have the chlorine pump set at 80. Does anyone have any ideas about why we still cannot detect any chlorine? Thanks in advance!
 

ditttohead

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We need a lot more information than that.

Injection Pump model number or pump injection rate.
Actual well pump flow rate, not the pumps rating.
Water treatment methods after injection ie: softener, contact tank, carbon tank, clinoptilolite, katalox light etc.

Send some pictures.
 

jrsummersill1

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Here are the pictures of the set up and a picture of the model number from the chlorine pump. We also bought a carbon filter from the person that we bought the chlorine system from, but we haven't plumbed that in yet so the water we tested for the chlorine has not been filtered or treated (other than the chlorine) in any manner. We have drawn samples from an outlet on the other side of the tank and an spigot that is after the check valve but before the water enters the tank.

We have been testing the water for chlorine mainly with a pool test kit. We only took a sample to the pool store to see if there was a different result since we just can't understand why no chlorine is being detected when we know it is being injected.

According to the guy who installed our well, it pumps around 30 gallons per minute.
 

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ditttohead

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For starts, you need a proper chlorine test kit. I have dealt with chlorine testing for many years and pool test kits are simply not ideal for potable water testing. I prefer a photometer type of chlorine test kit. This simply uses a computer to determine the color of the water thereby taking the human eye which is horrible at seeing variations in color out of the equation.

As to the chlorine level in your water... why are you injecting chlorine? Have you had an accurate water test done. Chlorine is consumed in the treatment process so you need to inject to levels that slightly exceed the consumption.
If you have iron, manganese, h2s, etc... these will "consume" the chlorine thereby leaving you no residual.

If your pump is pumping at 30 gpm, you would need a fairly high dose to maintain any residual. here is a simple math equation to help you out.

Chemical injection pump GPG/Well pump output rate (GPD)xsolution strength= ppm injected.

I am not sure of your chemical injection pump but lets guess 10 gpd

10/43,200x6000ppm=1.4 ppm chlorine injection. If you have 2 ppm of iron, you will not have any residual chlorine.

FYI, a gallon of household bleach is approx. 55,000 ppm
 

jrsummersill1

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Yes, we did have a water test performed about a month ago by a local lab. The test showed that total coliform was present and that we had iron at .521 mg/L and sulfide at 2.85 mg/L. In doing some research, we assumed that with having an issue with bacteria, iron and hydrogen sulfide, chlorine followed by a carbon filter may be our best bet.

By the way, I really appreciate the information! That is very useful!
 
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Reach4

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How big is your well casing?

https://terrylove.com/forums/index.php?threads/well-sanitizing-extra-attention-to-4-inch-casing.65845/ is my write-up on well and system sanitizing without pellets. Even if you kill bacteria after it is out of the well, I think it is good to sanitize inside the well too.

Sanitizing the WH is important too IMO. Sacrificial anodes together with SRB can produce H2S in the WH. I have a powered anode, which does not have that effect. Some remove the sacrificial anode, and replace it with a brass plug. That can shorten WH life. Once a sacrificial anode is exhausted, it is as if it had been removed.
 

ditttohead

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As you can see by the math, knowing the parameters is very important. Guessing the flow rate of a pump does not really work well without have a good test kit. Also for bacteria, a contact tank is needed. H2S and iron, a contact tank is preferred.

So now you get to go about figuring out the real numbers. Here is a simple write up from my catalog that I wrote a while back. It should give you a good starting point.

Stenner®pumps have interchangeable pump tubes allowing them to be changed in the field to a larger or smaller size depending on your specific needs. Some simple math is all that is needed to have a successful chemical injection program.

The simple formula below will work for most of your chemical injection needs.

Stenner pump GPD / Well pump output rate (GPD) x Solution Strength (PPM) = PPM Injected.

Stenner Pump GPD: .2-3, .5-10, 1.1-22 GPD are the most common output rates. The maximum output of each pump is the number used for the equation.

Well Pump Output Rate: First, allow the well pump to build up pressure by running water in the home until you hear the well pump kick on or the pressure switch “clicks.” Close the faucet and wait for the pump to stop running. Open a spigot near the pump (after the pressure tank) into a five gallon bucket noting how many gallons you collect. As soon as the well pump turns on turn off the spigot and time the period in seconds it takes for the well pump to refill the pressure tank and shut off the well pump. (Gallons/Seconds) x 60 = GPM of the well pump.

Dosage in PPM: Typical Hydrogen peroxide H2O2 or chlorine (Cl2) injection is as simple as injecting enough oxidant to precipitate out the offending contaminant. The most common contaminants are listed below. Most applications recommend 1-2 ppm residual for hydrogen peroxide and 1 ppm residual for chlorine.

Solution Strength (PPM): Simply calculate the solution strength by dividing the ppm of the Hydrogen Peroxide (typical 7%=70,000 ppm) or chlorine (typical 6%=60,000 ppm) into the dilution ratio. 1 gallon 0f 7% H2O2 diluted with 30 gallons of water would = 2333 ppm.


Contaminant

Hydrogen Peroxide

Chlorine

Iron

1 ppm iron = .5 ppm H2O2

1 ppm iron = 1 ppm Cl2

Manganese

1 ppm manganese = 1 ppm H2O2

1 ppm manganese = 2 ppm Cl2

Hydrogen Sulfide

1 ppm hydrogen sulfide = 1.5 ppm H2O2

1 ppm hydrogen sulfide = 3 ppm Cl2
 

jrsummersill1

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I am still trying to digest the information you all have provided and I really do appreciate the information. We have a 4" well casing. We were not sure about the contact tank and our pressure tank is quite large--520 gallons. What size of a contact tank would we need? Would it come before or after the pressure tank?
 

ditttohead

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Post some pictures of all of your equipment and include a layout description.

Is a good chlorine test kit in your budget?

By what you have posted, it is unlikely you would have any chlorine residual even though you are pumping chlorine into your system. The chlorine is likely getting consumed before you are able to test for it.
 

jrsummersill1

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At the moment, I only have the images that I posted previously of the system. The layout is that the well, pressure tank and chlorine injector are about 300' or so from the house. So the water travels from the tank to a small 10" x 2.5" GAC filter (which will soon be replaced with a whole house carbon filter) which is located at the house end of the system.

How much does a good chlorine test kit cost? And can you post a link to one?

Yes, from what you all are saying, I do believe that the chlorine is being consumed, because we have put an awful lot of chlorine in there for it not to be detected by test or smell.
 

ditttohead

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about $150 for a photometer type that is highly accurate and repeatable. PM me for a link to where to buy it from.
 

jrsummersill1

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I just wanted to give a quick update. My husband came up with the idea to install a time delay device (I believe that is what it is called). Thus the chlorine injector still comes on when the well pump comes on, but then the chlorine injector actually stays on for a set period of time after the well pump quits and it continues to inject chlorine. We currently have it set to continue to inject chlorine for an additional 150 seconds after the well pump shuts off. We are now no longer having any problems detecting chlorine throughout our plumbing system except for in the house (and that is due to the carbon filter removing the chlorine). Also, we are no longer smelling the sulfur smell or seeing any iron staining. So hopefully we have solved our initial problem without having to purchase and install a contact tank.
 

Bannerman

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Normally, you would control the chlorine injector with a flow meter. Instead of the chlorine pump running only when the well pump operates, the injector would operate when any water is flowing from the pressure tank. With a 520 gallon pressure tank, a large volume of water maybe drawn before the well pump is activated.

Of course, chlorine would be injected after the pressure tank. Typically, there would be a contact tank located just before the carbon filter to permit the chlorine ample opportunity and time to mix and act to oxidize iron and sulfur. The contact tank also permits the oxidized solids to be easily ejected to drain so the carbon filter isn't dealing with an excessive solid load.

As your pressure tank and chlorine injection location is a long distance away from the home, perhaps a contact tank may not be as necessary. Since oxidation will cause iron and sulfur to precipitate from the water as solids, you may wish to incorporate a method to collect and periodically eject the bulk of solids from the water line, before the carbon filter.
 
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Reach4

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Of course, chlorine would be injected after the pressure tank.
Chlorine injected before the pressure tank is normal too. It is necessary when proportional injection is not used.
 

Bannerman

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Chlorine injected before the pressure tank is normal too.
Perhaps with a very small amount of iron/sulfur. With high iron, expect much iron sediment to cause potential blockage to the tank port including within the line between the tank and pressure switch.

Although in this case, the pressure tank is not a bladder type, high levels of chlorine contact with a bladder is typically not advised.
 

ditttohead

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By massively overdosing chlorine you will reduce the h2s. This can work off of several simple principals. The carbon can actually "store" excess chlorine but this is an old design that works, but if it is not properly controlled and the carbon is not replaced, chlorine bleed by will occur and usually incrementally. I have seen houses with several ppm of chlorine that the occupants couldn't detect since it came on slowly and over a long period of time. Kind of like the whole house ozone generators that were so popular years ago. I have walked into many houses where my eyes and lungs would start to burn... the homeowners thought it was fine...

Be sure to replace your carbon regularly and more importantly test regularly for any trace amounts getting by the carbon. Do not use a pool test kit, use a photometric test kit with reagents that are not expired...
 

jrsummersill1

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Dittohead,

We have used the pool test kit to test the water before and after the carbon filter and it shows some chlorine before the filter and none after the filter, but I will definitely keep in mind what you said about the carbon retaining the chlorine. I was just happy to see it being detected at all since before we modified the system with the time delay device we were not showing any at all.

We do not use the water to drink or cook with. Only bathing and washing clothes and dishes really. A few questions for you: Is any chlorine showing up after the filter acceptable (we don't detect any, but I understand that the pool test is not the most accurate way to go)? If so, how much is acceptable? How often do you recommend regenerating the carbon? And how often totally replacing it?

I am looking into something different to test the chlorine in the water with and those things can be quite expensive! Would something like this suffice?:




Thank you for your help and knowledge!
 
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