CH low, CSI ~0, concern?

[Kirkisg]

Not sure what happened, this past winter, the PH and TA did creep up to 8.1 and 120, and the calcium dropped from 230 down to 130. Added some calcium and brought it up a little.

Any long term concerns with CH - 170 if I maintain my TA and PH within a reasonable range? Any reason to try and increase CH to meet the minimum recommendation over 200?

Thanks!

 

[PoolStored]

Assuming you have a plaster pool...

What is the TA and CH of your fill water. If CH is high, you probable can get by with 200 and it will rise, if lower, you should get the calcium up to at least 250. It may require that you lower TA or run pH on the lower side to balance CSI.

Over time, water with low calcium levels will tend to dissolve calcium out of plaster, pebble, tile, stone, concrete, and to some extent fiberglass surfaces. You can prevent this from happening by keeping the water properly saturated with calcium.

Calcium Hardness - Further Reading

www.troublefreepool.com

 

[Kirkisg]

Assuming you have a plaster pool...

What is the TA and CH of your fill water. If CH is high, you probable can get by with 200 and it will rise, if lower, you should get the calcium up to at least 250. It may require that you lower TA or run pH on the lower side to balance CSI.

Over time, water with low calcium levels will tend to dissolve calcium out of plaster, pebble, tile, stone, concrete, and to some extent fiberglass surfaces. You can prevent this from happening by keeping the water properly saturated with calcium.

Calcium Hardness - Further Reading

www.troublefreepool.com

So even with a perfect CSI, I may still see issues with the flagstone and pebbletec?
City water CH is low, I think that also contributed to the decrease this winter.

 

[PoolStored]

City water CH is low, I think that also contributed to the decrease this winter.

From the article I linked...

Calcium hardness (CH) is the direct measure of the amount of calcium ions (Ca2+) in your pool water.

Over time, water with low calcium levels will tend to dissolve calcium out of plaster, pebble, tile, stone, concrete, and to some extent fiberglass surfaces. You can prevent this from happening by keeping the water properly saturated with calcium.

From the next article linked here:
CSI is nothing more than a measure of how over-saturated or under-saturated your water is with calcium carbonate.
– Pools who tend to have extremely hard water or excessively high alkalinity (potential for scale)
– Pools that tend to have naturally soft water or low alkalinity (potential for erosion-plaster only)
– Salt Water Generator (SWG) owners (scale on cell plates)
– Pools with waterline tile (potential for scale or erosion)
– Newly plastered pools; especially those recently completed and closed before winter (potential for dramatic pH increases)

Do one of these ^^^ apply?

Calcium Saturation Index (CSI)

How is CSI calculated? Very simple – use our PoolMath tool. To ensure long plaster life and save money, click here to learn more.

www.troublefreepool.com

pebbletec?

^^^This. Over time, water with low calcium levels will tend to dissolve calcium out of plaster, pebble...

 

[Kirkisg]

From the article I linked...

Calcium hardness (CH) is the direct measure of the amount of calcium ions (Ca2+) in your pool water.

Over time, water with low calcium levels will tend to dissolve calcium out of plaster, pebble, tile, stone, concrete, and to some extent fiberglass surfaces. You can prevent this from happening by keeping the water properly saturated with calcium.

From the next article linked here:
CSI is nothing more than a measure of how over-saturated or under-saturated your water is with calcium carbonate.
– Pools who tend to have extremely hard water or excessively high alkalinity (potential for scale)
– Pools that tend to have naturally soft water or low alkalinity (potential for erosion-plaster only)
– Salt Water Generator (SWG) owners (scale on cell plates)
– Pools with waterline tile (potential for scale or erosion)
– Newly plastered pools; especially those recently completed and closed before winter (potential for dramatic pH increases)

Do one of these ^^^ apply?

Calcium Saturation Index (CSI)

How is CSI calculated? Very simple – use our PoolMath tool. To ensure long plaster life and save money, click here to learn more.

www.troublefreepool.com

^^^This. Over time, water with low calcium levels will tend to dissolve calcium out of plaster, pebble...

I get it, I just have more of an issue currently with scale. It seems counterintuitive to add calcium to prevent a problem I don’t have, while potentially making a problem I do have worse.

 

[PoolStored]

I get it, I just have more of an issue currently with scale. It seems counterintuitive to add calcium to prevent a problem I don’t have, while potentially making a problem I do have worse.

New plaster and scale are both expensive.

Update your CYA to 60. You only read CYA at the lines, no in-betweenies as the scale is logarithmic.

Upping your CH to 250 will put your CSI at .35. Lowering your TA to 100 brings CSI down to .05.

Cheap solution to solve both problems...

Lower Total Alkalinity

A lower Total Alkalinity level can help a pool owner stabalize their pH increase. We'll explain how to lower TA with a little help from muriatic acid.

www.troublefreepool.com

 

[PoolStored]

What is the TA of your fill water?

 

[PoolStored]

Here is what I did. I have a sump pump. I built this out of PVC and mounted it to the sump. I found the trick to raising pH (in the Lower Total Alkalinity article) is to reduce pH to 7.0 when you start (CO2 outgasses at the highest rate when pH is low), then you want to make A LOT of VERY TINY bubbles. I can lower TA by 10 in 12 hours with this method. I have a largish pool.

If you have water features, those work great too.

Aerator.jpg

• PoolStored
• Jul 5, 2022

 

[Kirkisg]

Thanks for the responses. Still learning in my 2nd season maintaining the pool. My cya was creeping over 120 last year, so I aggressively tried to get it below 50, then I hit under 40 and could noticeably see the difference, chlorine was disappearing quick! I’ll add some calcium and get my numbers right.