Low calcium

[AlexPowell]

Hi everyone:

65,000 Litres, Plaster painted with vinyl.
FC 8
pH 7.8
TA 90
CH 125
CYA 50
TDS 4000

I would like to bring Calcium to to around 550 as per the recommendations. This would be 31kg of Calcium Chloride.
I have never added Calcium, so CH of 125 is indicative of my tap water, however I will take a test of my tap water as well to be sure.

I am nervous about adding such a large volume of CaCl at once. Should I add around 4kg a week and test each time or am I fine to - as we say in Australia - "f-ing send it"?

 

[JoyfulNoise]

Why would you want to raise your CH to 550ppm? That’s totally unnecessary …

 

[AlexPowell]

Why would you want to raise your CH to 550ppm? That’s totally unnecessary …

Thank you again for helping me

These are the recommendations given by the PoolMath app

 

[JoyfulNoise]

You can set the target value to anything you want. There’s nothing magical about 550ppm CH. 125ppm CH is just as acceptable under some circumstances. Mineral hardness is something that will build up in your pool water over time from fill water added to offset evaporation unless you get enormous amounts of rain overflow. Calcium hardness has no interaction with other chemicals in the pool so there is no reason to raise it arbitrarily. Calcium hardness only matters when you have a plaster pool surface and you want to make sure your water is not aggressive towards that surface by tracking the calcite saturation index. But even then, the CSI can be more easily adjusted using pH and TA. Your signature says that you have a painted pool surface. Paint, while not a very good surface material for pools, does not require calcium saturation. Your pool is more like a vinyl pool than a plaster pool.

Finally you have a saltwater chlorine generator. Those units can generate a lot of scale if the calcium gets too high even when the saturation balance is negative. So having low CH is much better than high CH for any given CSI value.

Short answer - don’t bother raising CH, you don’t need to.

 

[AlexPowell]

You can set the target value to anything you want. There’s nothing magical about 550ppm CH. 125ppm CH is just as acceptable under some circumstances. Mineral hardness is something that will build up in your pool water over time from fill water added to offset evaporation unless you get enormous amounts of rain overflow. Calcium hardness has no interaction with other chemicals in the pool so there is no reason to raise it arbitrarily. Calcium hardness only matters when you have a plaster pool surface and you want to make sure your water is not aggressive towards that surface by tracking the calcite saturation index. But even then, the CSI can be more easily adjusted using pH and TA. Your signature says that you have a painted pool surface. Paint, while not a very good surface material for pools, does not require calcium saturation. Your pool is more like a vinyl pool than a plaster pool.

Finally you have a saltwater chlorine generator. Those units can generate a lot of scale if the calcium gets too high even when the saturation balance is negative. So having low CH is much better than high CH for any given CSI value.

Short answer - don’t bother raising CH, you don’t need to.

Thank you kindly