Calcium level?

[Brekel]

Hi all.

I've bought and moved into a house with a 1,800 gal swim spa, and I'm getting the parameters under control from some issues that existed when I moved in (eg FC over 100, but that's a whole different story!).

After reading through the recommendations in the spa sticky on how to use chlorine, (as well as LOTS of other stuff here on TFP) I just have one question.

Using the recommended parameters in How do I use Chlorine in my Spa (or pool)? , and plugging the numbers into poolmath, everything seems reasonable if the salt level is low. However my spa has an SWG. If I put the recommended 4,500ppm salt into poolmath, it takes the CSI down below -0.6.

I don't want to raise the TA to much as I understand that will cause pH rises with the aeration. Should I increase the CH to compensate and raise the CSI? Or doesn't the CSI matter? The pool has an acrylic surface so the CSI shouldn't affect it, but some other threads indicate that there may be an issue with ceramic components in the heater/pumps?

Your thoughts would be appreciated.

 

[pooldv]

Negative CSI is only bad in plaster pools. As long as it is negative you are fine, what you don't want is positive CSI leading to scaling.

Nice job reading up! I've been maintaining my hot tub with that process for years and it is great!

 

[Brekel]

Thanks pooldv.
In the posts on the same thread on spa's, chem geek commented on hearing about some unspecified ceramic components that may possibly require calcium saturation. It was a bit vague based on what he'd heard from others. Is this now thought to not be the case?

I guess if people like yourself are successfully using the parameters listed, it's probably ok

The previous owned had an issue with two heaters failing, so I just want to make sure my water parameters are acceptable. The second replacement was just after we purchased the place (covered by original owner's warranty as it failed before they left), but unfortunately I didn't get to see inside the old heater tube to check for deposits/corrosion.