Calcium Hardness "affecting chemical balances"

[zeezsal]

I just visited the local pool store and was told my CH is too low (160ppm) and adding calcium will keep other chemicals from "wavering" too much. Specifically, the employee said my pH and alkalinity are more likely to "stay put" if the hardness is above 200ppm.

Learning from past mistakes, I refused to purchase calcium before consulting Trouble Free Pool! Just as I suspected, I learned from other threads that vinyl pools don't require calcium.

I'm still perplexed though- has anyone heard of Calcium Hardness affecting other chemical levels? She made it sound like it was a vital stabilizer of sorts.

 

[Leebo]

What is your pool surface?

 

[JasonLion]

As is so often true of this kind of things, there is a tiny grain of truth behind that statement, even though it is false as stated. In vinyl and fiberglass pools, CH will not have any effect worth mentioning on any other level. In fiberglass pools CH levels can affect the lifetime of the gel coat, but that won't affect anything else. In plaster pools CH levels don't usually have any effect. However, if the CH level is very very high or very very low you can experience calcium scaling or plaster pitting respectively, and if either of those happens there will be a noticeable effect on both PH and TA.

To sum up, as long as your levels are reasonably balanced, CH will never affect other levels. However, if CH is extremely far out of balance, and you have a plaster/gunite/pebble/quartz pool, there can be serious problems and those problems can affect some of your other levels.

 

[zeezsal]

I have a vinyl pool, as i explicitly stated before the employee tested the water.

It was hard to trust her suggestions because she exclaimed my water "is wayyyyy to soft!" but the CH was just 160ppm.