rainwater dilution, negative csi.

[bobby1017]

I wanted to lower the salt level in my pool and the CH some. My ic-40 is set at 8%, pump runs 8 hrs per day.I put the pump on the cover and the hose into the pool, we recieved approx 3" of rain. Here are the old numbers and then the new.

fc 4.5
cc 0
tc 4.5
ph 7.5
ta 70
ch 340
cya 55
salt 3600
temp 63

As of this am, I didn't check the cya.

fc 4.0
cc 0
tc 4.0
ph 7.4
ta 60
ch 290
cya ???
salt 3400
temp 60

The results were somewhat what I expected. I plan on adding another dose of cya to raise that some. My worry is now the csi is -.79. I know the value of csi is debated. Should I do something about it?

 

[Richard320]

Let it mix some more and then recheck.

 

[JasonLion]

-0.79 us getting down there, and adding some CYA will take it lower. With TA that low, the PH isn't going to come back up very quickly, though it will come back up eventually. I suggesting raising the PH just a little, say to 7.6.

 

[bobby1017]

So if I add baking soda I can raise the ta & the ph at the same time per the pool calc. To raise ta by 10 add 68 oz. Not sure how much the ph will rise. If I get the ta back to 70 and the ph to 7.6 I'll be at -.51 csi.

 

[JasonLion]

Baking soda has only a very small effect on PH, it should be better to use soda ash, at least if you have some.

 

[bobby1017]

I already had baking soda so I used that, added 80 oz. The new numbers are better as far as the csi goes, it's now -.51. It's always somewhat hard to get a good ph reading, it may be a little more than 7.5. I attribute the rise in ch to the water being mixed better today.If the water gets warmer that will help also.

fc 5.5
cc 0
tc 5.5
ph 7.5
ta 70
ch 310
cya (was 55 before the addition of 3" of rain)
salt 3400
temp 62