CSI too high?

[stevenl241]

Hi,

Using TFP method this year, first time, great results - sparkling clear, no algae, no shocking...easy. (Except for disposing of the empty liquid chlorine jugs.)

But my question is around Calcium Saturation Index. Poolmath is giving me +.41 and I'm getting concerned about damaging the plaster which is already kind of rough.

Using TF100 test kit:
FC: 4.0
CC: 0
CH: 400
TA: 100
PH: 7.8
CYA: 50

I feel like I should get the PH down to 7.4-ish.
I've put in enough dry acid to do so, but the PH only went down to 7.6, and then back up to 7.8 within a week.
BTW I've owned the pool for two years - there appears to be some calcium scaling through-out the pool (patchy/streaky areas) but it hasn't changed over the past two years (brushing doesn't seem to help.)

Should I be concerned?
Should I try to overshoot the PH down to 7.something?
Should I drain and refill to lower CH? (Expensive - local tap water CH measures 200, so I'd have to truck in water.)

Thanks a lot for any comments!

Steve

 

[Richard320]

Plug all your numbers into poolmath in the Now and Target columns. Then go play with the different variables. You'll be surprised to fin out how little effect CH actually has on CSI, and how much temperature has. You'll also see how lowering pH and/or TA can easily drive that number deep into negative territory. They are the critical numbers, really.

The simplest thing to do is to lower pH to 7.2. This will also lower TA. Plug your numbers in and then go waaaay down to Effects of Adding Chemicals and see just how much TA will drop by the addition of whatever acid you need to lower pH. Just keep knocking pH back to 7.2 whenever it starts to approach 7.8 and the TA will lower substantially and the CSI will shift more to neutral.