Dilution of old CaCO3

[DetRack]

Hi and merry christmas

our water softener has been up and running for three weeks and is doing a fine job 5.1cbm = about 1341 gallons were softened in the time. Our pipes are 30-50 years old and have substantial limestone buildup. While the flow is still acceptable, there is not much headroom left.

In the first two weeks, i measured 3gpg in hot water and 2 gpg in cold water. After two weeks, both went down to less than 0.5gpg which is the minimum with my hardness drops (1 drop =1 gpg, or 0.5gpg in a bigger sample).

I was hoping for the soft water to dissolve some limestone. Since the hardness dropped from 2 and 3 to <=0.5, there is not much hope left.

What hardness should I expect from softened water that passed through about 60 feet of old pipes with lots of deposit, is there some hope that more CaCO3 dissolves after the initial success? I suppose the initial water hardness came from fresh calcite that wasn't fully hardened.

Best,

Detlev

 

[Bannerman]

1 grain per gallon hardness = 17.1 ppm.

The 0.5 gpg hardness will most likely be resulting from calcium being slowly dissolved from within the pipes, which could occur for some time yet, possibly years if the mineral accumulation is substantial. See Ditttohead's comments in post #23 in this thread: https://terrylove.com/forums/index....always-feel-slippery.83160/page-2#post-600059

Also, be aware there will be some hardness leakage which will occur through the softener as determined by the salt and capacity settings chosen. For anticipated leakage amounts, see the bottom of the chart in post #21 in the same thread.

While this hardness leakage will not normally occur from the outset with the resin fully regenerated initially in a new softener, your softener contains a small quantity of resin so the amount of contact time with the resin is severely limited. With limited contact, hardness leakage through the softener is more likely to occur when water is flowing even at a reduced flow rate.

 

[Sponsor]

 

[Reach4]

What hardness should I expect from softened water that passed through about 60 feet of old pipes with lots of deposit, is there some hope that more CaCO3 dissolves after the initial success? I suppose the initial water hardness came from fresh calcite that wasn't fully hardened.

I don't know what to expect, but perhaps you could consider filling your pipes with a suitable acid, such as white vinegar (5% acetic acid) to dissolve the hardness compounds faster?

Have you flushed your water heater? Tank or tankless?

 

[DetRack]

The tank of the heater gets flushed during the yearly maintenance, that was just a week before the softener was installed. The central heating is a Buderus system for >10k, I'm not touching that myself

Using vinegar sounds like a plan. I just need to find a day where this can rest in the system, maybe over a vacation.

in the meantime I'll get a 0.1/0.05° test kit and compare readings from the test-cock at the bypass and a faucet.

Thank you for your feedback

 

[DetRack]

So I got my residual hardness kit today. It consists of two bottles. First one drop of "RF-1" which is clear, then "RF-2" until the sample turns green. The resolution is 0.1 GPG per drop.

The results:

0.1 GPG at the bypass (test-cock)
0.4 GPG from a cold-water faucet in the bathroom
0.6 GPG from the hot-water faucet in the bathroom

All numbers were taken with one faucet fully open.

So in fact my softener does slowly remove limestone from my plumbing, it's just so little that a regular hardness-test can not prove it.

I will just wait-out the process in the house-plumbing.

There was one known bottlekneck in the system, that the plumber showed me when he installed the softener. The service line enters the house at ground-level in the basement, and continues horizontally until the meter. After that, an ellbow turns upwards, about 7 feet to the ceiling-level. This ellbow was badly clogged. It was opened on one end for the installation of the by-pass, and I could see that my small finger would not pass.

My wife would not let me exchange this short part of the main-line, so I decided to go chemical. When the family was out for 2 hours during the holidays, I isolated the affected two feet of pipe and filled them with concentrated amido-sulfuric acid. After two hours, flushing brought out a spectacular yellow mass. The dynamic pressure at the sediment filter gained about 7 psi just from this treatment.

Best,

Detlev

 

[Reach4]

When the family was out for 2 hours during the holidays, I isolated the affected two feet of pipe and filled them with concentrated amido-sulfuric acid. After two hours, flushing brought out a spectacular yellow mass.

Maybe that grew in your non-chlorinated water.

 

[DetRack]

It was just a mix of calcite and a bit of rust from the galvanized steel.

Amido-sulfuric acid is the best stuff I know for limestone removal. It's used in professional coffee machines, it's cheap when bought in volume, and it's not aggressive to plastic seals and tubing.

I wouldn't use it on paper seals, as it affects organic matter. And protective glasses are a must.