Question about poolmath target ranges and CSI

[Crazy Clownfish]

Have a vinyl pool with SWG for 3 years. Thanks to TFP pool chemistry info, it has been easy to keep water clear and trouble free
Have a question about calcium and CSI please. Using poolmath app for the below chemistry and it calculates -0.68 CSI. They are all within or close to recommended range. What adjustments should I make to get CSI to above -0.3?
pH 7.6
TA 82
CH 121
CYA 50
Water temp 70 F - don't have heater so can't change this.
Salt 3200
CSI -0.68
Thanks in advance for any advise and guidance!

 

[mknauss]

Welcome to posting!
No need to worry about CSI on the low side. You have a vinyl liner.

 

[Crazy Clownfish]

Thank you for the quick reply!
Curious, what about CSI concerns for pump and equipment?

 

[mknauss]

No effect.

Your data implies a pool store test. Be ware they are not accurate.

 

[mavitia22]

Welcome to posting!
No need to worry about CSI on the low side. You have a vinyl liner.

Hi, I'm reading this old thread, and I wanted to ask you about the CSI and calcium. I see you have a fiberglass saltwater pool like me. My manufacturer suggests calcium level be 80-120, CYA 30-50, and Ph 7.2 -7.4
My levels:
FC - 3
PH - 7.8
TA - 90
CH - 130
CYA - 30
Salt - 2300
TEMP - 83°
CSI - 0.21
If I try to lower ph to 7.6, it brings my CSI below -0.3. I see you replied not to worry about calcium since it's a vinyl liner. Was wondering what your calcium levels are. I'm wanting to add more calcium, but I emailed the pool manufacturer and they said to leave it as is and not worry too much about the CSI. (Umm, I still worry.)

Do you think I should add some calcium, or do you think I need it in the fiberglass pool? I've read so many different articles and opinions on what the levels should be in a fiberglass pool. Any help is appreciated! Thank you!

 

[nobody291]

Do you think I should add some calcium, or do you think I need it in the fiberglass pool?

Negative CSI isn't a concern in a fiberglass pool, it is only a concern in plaster-based pools since a negative CSI can leech calcium from the pool plaster and weaken it. Positive CSI is a concern in all pools since it can lead to calcium scaling and other problems. Depending on it's composition, your fill water might be adding calcium to your pool water, in which case, your CH level will rise over time (and is another good reason to not add any now).

 

[mavitia22]

Ok, sounds good to me. Thanks again!