Use Saturation index or Real Numbers???

Rockcrawler

Well-known member
#1
Heres the deal and my question, my pool 13000 IG plaster, the Taylor book says ideal range for the follow PH 7.4-7.6 CH 150-400,TA 80-120 CYA 30-50 and the saturation Index should be <>.5 now my question if I use the data in the book, my numbers are out of wack,except for my TA, but if I use the Saturation Index I am within the limits. I am using BBB method, and slowly but surely I am bringing down my CYA and CH, I know the reasons why these numbers are so high, when I first had the pool built I was "dumb" I kept on adding calcium hypo pucks and trichlor pucks, thus my high readings, slowly but surely my numbers are dropping, I have done partial drain and refill to get them down to this, and will now wait for splash out and backwash to get them down to where the "book" says they should be. But, for the time being should I use the Saturation index to keep my pool "balanced" or use the book???? and because my CH and CYA especially my CH is so high, should I go ahead and do another partial drain and refill, or is my pool plaster safe.

Sorry for the long post, I might be making a "big" deal out of nothing, just want to make sure, and my water is sparkling clear

Thanks for you advice in advance

Pool Temp 78 degrees
FC 6
TC 6
CC 0
PH 7.2
TA 100
CH 700
CYA 70
 

JasonLion

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May 7, 2007
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#2
The goal is to get everything into balance all at once, both the ideal ranges and the saturation index. However, that isn't always practical. There are various ways you can compensate when you can't get one or another of the numbers into range. For example the main issue with high CH levels is that the saturation index tends to get too high so you can compensate by lowering PH and/or TA. On the other hand you want to keep PH within 7.2 to 7.8 regardless of other issues to avoid eye irritation.
 
G
#3
If you are using unstabilized chlorine (bleach) then you want to run your TA lower than suggested to get better pH stability. Since you have high CH this is ideal for you. Bring your TA down to around 60 ppm and keep your pH between 7.6-7.8
 

Rockcrawler

Well-known member
#4
Thanks waterbear and jason for replying

Yes I am using bleach for my sanitation, thanks waterbear for the tip on the TA I will lower it to about 60 for PH stability, so you guys don't think that the high CH is worth a partial drain and refill???? just wait for splash out/backwash??? just curious waterbear why is haveing high CH ideal? whats the benefit??
 

duraleigh

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#5
Waterbear is saying that BECAUSE you have high CH, the adjustments he is suggesting will help you compensate.

IMO, high CH is never ideal and I would suggest you drain and refill. I personally do not think the vast majority of us chem dummies need to use CSI. If you simply saty within the parameters suggested as normal, that's all you need to keep your pool water balanced.

I realize it (CSI) can provide additional information but NASA and MIT could probably give me more info about my pool, too......I just don't want to overthink it too much. My personal comfort level is to stay within the testing for Cl, pH, Alk, CH, and CYA.
 

JasonLion

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Silver Spring, MD
#6
The issue of a partial drain and refill has to do with the CH level of your fill water and the evaporation rate in your area. People who live in semi-desert climates with high CH fill water and high evaporation rates have to learn to deal with high CH levels. In those conditions CH goes up quickly and you want to put off the partial drain and refill as long as possible. If you have a lower evaporation rate (ie humid summers) and reasonable CH levels in your fill water (for example under 150) then now would be a good time to do a partial drain and refill to get the CH level down.
 
G
#7
Your other option, if you have a water softener, is to use softened water to top off your pool when needed. If you always do this you might actually have to ADD calcium one day.