Spa water chemistry

[Capgun42]

Moved from here

The only time you need to wait longer than an hour, with the pump running, is when adding calcium. You don't want to do anything that raises the PH for 24 hours after adding calcium. So no borax, PH Up, soda ash, washing soda, baking soda, cal-hypo, or bleach for 24 hours after adding calcium.

Jason - Thanks for the info.

So, just to clarify, we do not need to worry about adding calcium to the water unless we have also added SpaUp/Down (or some other PH increaser/sodium bicarbonate) in the last 24-hours, and don't plan to add any for 24-hours after adding the calcium?

Also, is there any reason why calcium would decrease in a spa over time? I had a good level of hardness a few days ago, but now it has dropped to zero. No water has been added or removed.

Thank!

 

[Spa Owner]

Moved from here




Jason - Thanks for the info.

So, just to clarify, we do not need to worry about adding calcium to the water unless we have also added SpaUp/Down (or some other PH increaser/sodium bicarbonate) in the last 24-hours, and don't plan to add any for 24-hours after adding the calcium?

Also, is there any reason why calcium would decrease in a spa over time? I had a good level of hardness a few days ago, but now it has dropped to zero. No water has been added or removed.

Thank!

How are you testing? When you say hardness at a good level what is that level? A few days is a week or three? Has the spa been used?