Reducing Calcium Hardness

[DanWallace]

Over the past 2-3 seasons my vinyl liner has slowly formed a white layer of buildup which encompasses nearly 100% of the pool surface, which my best guess is that my hardwater is the culprit. Since 2018 my CH has gradually climbed from 130 PPM to its current level of 510 PPM. I did attempt to eliminate the buildup with "scale free" earlier this season, but it seemed to be ineffective.

Outside of minimal assistance from the rain, I replenish my pool with my city water. I strictly utilize liquid chlorine (12.5%), muriatic acid (31.45%) and chlorine stabilizer. I maintain a CYA of 40, PH of 7.4-7.6 and a TA of 80. May be noteworthy to point out that my TA also increases by roughly 10 PPM per inch of water added to replenish (TA reduced via aeration process).

I know that draining/replenishing my water would be the common resolution to reduce my CH, but it seems like that would be counterproductive in my scenario.

Would anyone have any guidance/suggestions on additional options for reducing my CH? Thanks in advance for the assistance. Dan

 

[Bperry]

Over the past 2-3 seasons my vinyl liner has slowly formed a white layer of buildup which encompasses nearly 100% of the pool surface, which my best guess is that my hardwater is the culprit. Since 2018 my CH has gradually climbed from 130 PPM to its current level of 510 PPM. I did attempt to eliminate the buildup with "scale free" earlier this season, but it seemed to be ineffective.

Outside of minimal assistance from the rain, I replenish my pool with my city water. I strictly utilize liquid chlorine (12.5%), muriatic acid (31.45%) and chlorine stabilizer. I maintain a CYA of 40, PH of 7.4-7.6 and a TA of 80. May be noteworthy to point out that my TA also increases by roughly 10 PPM per inch of water added to replenish (TA reduced via aeration process).

I know that draining/replenishing my water would be the common resolution to reduce my CH, but it seems like that would be counterproductive in my scenario.

Would anyone have any guidance/suggestions on additional options for reducing my CH? Thanks in advance for the assistance. Dan

How are you testing the water? CH of 550 isn’t all that high.

 

[sande005]

There is really no other way to lower CH.
But as Bperry noted, your numbers are actually pretty good. You CSI score is +0.1, which is excellent.
So let's look at how you are testing, to validate, and then can explore what the issue might really be.

 

[aussieta]

what is the ta and ch of your fill water

 

[DanWallace]

How are you testing the water? CH of 550 isn’t all that high.

I utilize the Taylor K2006C test kit. I almost always test daily and never exceed two days without testing.

My concern with the CH is based on a few elements. One being that TFP stating the recommended high end is 650 PPM, which I anticipate approaching next year. Second, the formation of the white buildup on my liner. Lastly, the potential for issues with my copper heat exchanger.

 

[Bperry]

I utilize the Taylor K2006C test kit. I almost always test daily and never exceed two days without testing.

My concern with the CH is based on a few elements. One being that TFP stating the recommended high end is 650 PPM, which I anticipate approaching next year. Second, the formation of the white buildup on my liner. Lastly, the potential for issues with my copper heat exchanger.

If you can scoop up some of the white powder into a plastic bowl and put a drop of muriatic acid on it, you can confirm it’s calcium if it fizzles noticably. If not, it’s something else.

The only way to get rid of calcium is replacing the water.

 

[DanWallace]

I tested my source water today and it yielded a CH of 380 and a TA of 280. Most recent test of source water was in June and it yielded a CH of 630, TA was not verified at that time. No changes to source water made on my end, so the city must have made adjustments to their treatment.

 

[JamesW]

PH of 7.4-7.6 and a TA of 80.

Lower the TA to about 50 or 60.

Let the pH go up to about 7.8 as long as the CSI does not go above 0.0.

 

[JamesW]

Are you using PoolMath to log your results?

Turn on CSI tracking and keep the CSI between about -0.3 and 0.0.

 

[DanWallace]

There are no loose particles to capture and test with muriatic acid. My assumption of it being calcium buildup is based on my known issues with hard water within other areas of my home (water faucet buildup, deposits in coffee maker, etc.) and how the buildup in the pool is slowly worsening. Maybe it is noteworthy to point out that I can use a magic eraser to remove the build up on my liner.

I included a couple pics for reference.

Thanks again for the support.

 

[DanWallace]

Are you using PoolMath to log your results?

Turn on CSI tracking and keep the CSI between about -0.3 and 0.0.

I use the old school PoolMath web page to enter my test results to get my treatment values. No formal logging though. My CSI tends to sit around +0.2. On occasion it has climbed and fallen nearing both +/- 0.5.

 

[DanWallace]

Lower the TA to about 50 or 60.

Let the pH go up to about 7.8 as long as the CSI does not go above 0.0.

Would you recommend that I follow the aeration process to reduce my TA?

 

[JamesW]

I do not think that aeration is necessary for most people.

 

[proavia]

I use the old school PoolMath web page to enter my test results to get my treatment values. No formal logging though. My CSI tends to sit around +0.2. On occasion it has climbed and fallen nearing both +/- 0.5.

You do have the PoolMath app linked to your forum account already.
Update the PoolMath on your phone and use it to log your results.
If using the payware version of the app, all your logs will be save. If using the freeware version of the app, only your last save log will show.

 

[sande005]

What's the white granular stuff near and on the ladder base mat? If suspected CH build up, can you get the mat out of the pool and test it with acid?

 

[DanWallace]

I do not think that aeration is necessary for most people.

My apologies for the delayed follow up.

Is there a particular product that is recommended to reduce my TA? The only method I've used is, what I believe to be called, the aeration process (lowering PH to 7.0, then create aggressive bubbles with the return jet to raise PH to 8.0 and repeat until target TA is reached).

 

[DanWallace]

What's the white granular stuff near and on the ladder base mat? If suspected CH build up, can you get the mat out of the pool and test it with acid?

Other than some dirt I think that is a glare/reflection in the picture appearing to be white granules. There's definitely no loose particles of the white substance. I will try testing the mat as I believe there is some build up on it.

 

[dereksanders]

FWIW, my TA and pH are stable at 80 and 7.8. It’s happy and so am I.

What’s recommended to lower pH/TA is MA.

 

[mas985]

My apologies for the delayed follow up.

Is there a particular product that is recommended to reduce my TA? The only method I've used is, what I believe to be called, the aeration process (lowering PH to 7.0, then create aggressive bubbles with the return jet to raise PH to 8.0 and repeat until target TA is reached).

Creating "aggressive bubbles" is optional and only speeds up the process. If you just target a CSI of -0.3 with periodic dosing of MA to bring PH down to 7.2, TA will drop as well even without forced aeration. Targeting CSI takes care of both PH and TA. You don't need to wait to add MA until PH rises to 8. In fact, you don't want to allow CSI to climb above 0. A target -0.3>CSI>0 should avoid further scaling but you may need to go a little lower.

I am bit more aggressive when it comes to CSI because I have both a plaster pool and SWG so I usually target -0.6>CSI>-0.3.

 

[JamesW]

lowering PH to 7.0, then create aggressive bubbles

If you pour soda or beer into a glass, the carbon dioxide will come out over time on its own.

It you shake the beverage, it makes the CO2 come out faster.

If you heat the water, the CO2 comes out faster.

If you boil a pot of water, the first bubbles that are formed are from dissolved gasses coming out of solution, not water converting into steam.

It is the same thing with pool water, the CO2 comes out on its own over time with no agitation or heat.

Heat and agitation speed up the process, but it is not worth the time and effort to speed it up over the process that happens naturally.