do not have a recent well test. I was supplied the original from well drilling circa 2001. Not sure if even relevant 25 years later.
Water conditions may have changed significantly over that time period. Generally recommended for well owners to have their raw water tested at least every 3-5 years. A private well owner is the water supplier and so the well's owner is fully responsible for water conditions and safety.
As no water test has been perform over a long time period, suggest obtaining a lab test right away. If the new test indicates conditions have changed significantly since the previous test, then you probably should have the water retested again after 1-2 years. That increased inital testing frequency should then indicate if conditions continue to change, and if so, at what rate.
While it is not this forum's purpose to recommend suppliers or testing labs, you may not know of any. National Labs is frequently recommended as they specialize in both Well and Municipal water testing, and they offer a comprehensive detailed written report that is straightforward to understand.
1 part 12% chlorine mixed with 7.5 parts water, results in a chlorine solution strength of 1.41% when the solution is initially prepared. Diluted solution will typically undergo slower flash off than undiluted chlorine, but the usual recommendation will be to mix sufficient solution for consumption within 30 days or less. If too much solution is being prepared, then significant flash off maybe occuring, so any remaining solution being injected, may not provide much of any benefit, perhaps closer to injecting plain water.
Because the water flow rate varies in relation to the constant rate that chlorine is injected, we can't really calculate the strength of chlorine within the tank. As the flow switch is located on the exit pipe at the top, any water exiting the retention tank through an alternate pathway such as the water discharged during blowdown, will not cause the Stenner pump to run.
tested with the expired strips post holding tank, pre carbon. Not detecting a visual change on the strips for what that is worth.
I interpret this to mean no difference in the amount of chlorine measured post retention tank vs post carbon tank. I also anticipate, no chlorine was indicated whatsoever.
When the chlorine entering the retention tank is less than required to oxidize the full quantity of ferrous iron, manganese or hydrogen sulfide (H2S), or to neutralize bacteria, then the chlorine will be consumed and there will be no residual chlorine measured exiting from the retention tank. To assist to ensure all of the chlorine remains active throughout the entire tank, there is to be residual chlorine present in the outflow, which should be minimally 0.2ppm, but ideally, 0.3 - 1.0 ppm. The residual chlorine will then be removed by the carbon filter that follows.
When there is insufficient chlorine for the water conditions, then some amount of ferrous iron, manganese and H2S will pass through the tank into the carbon filter. While the carbon may reduce some H2S if present, it will not remove ferrous iron or manganese, so those elements will proceed-on to the softener.
While a softener is capable of removing some amount of ferrous iron and manganese, I anticipate your softener had not been programmed for that additional load since it had likely been anticipated for the ferrous elements to have been oxidized and removed within prior retention and carbon tanks. When softening resin is exposed to ongoing ferrous iron and/or manganese, those elements will accumulate on the softening resin, therby resulting in the resin becoming fouled and less effective. To restore softening capacity and proper operation, will then require either replacement of the resin and gravel, or possibly removing the accumulation from the resin using strong applications of Super Iron Out, Citric Acid or other acid based resin cleaner.
This tank is 120 gallon. Well-made UT120.
That tank is Standard, not equipped with baffles. Baffles ensure the solution will be thoroughly mixed with the water and, will alter the internal flow path so incoming water cannot be directed toward the top outlet port. Baffles then assst in maximizing contact time for the chlorine to act on the ferrous iron, manganese and H2S before the treated water exits from the tank.
A 120 gallon retention tank, even when water is flowing at a higher than average rate of 8 GPM, should then result in 15-minutes contact time which is usually more than sufficient. If the flow rate is a more common 6 GPM or less, typically occuring in a single family residence, contact time will be 20-minutes or longer.
there is a blowback valve. I open it 1/4 turn every 30 days for 1 minute.
As water conditions may have significantly changed over 25 years, that blowdown frequency and duration could potentially be insufficient, but, you have no ability to monitor the discharge.
You might consider installing a short section of clear tubing into the drain line so you can al least observe when the discharge becomes clear. If there is significant debris being eliminated, it's likely that some accumulation will occur within the tubing over time and so the tubing section will probably need to be periodically replaced.
