Assistance with a CSI target for my pool

shacke

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Jul 5, 2010
134
Philadelphia
Thanks to the forum my chemistry is finally bangin' :goodjob:

Todays chemistry:

FC 8
pH 7.3-4
TA 70
CH 200
CYA 80
Temp 82

Based on the pool calculator, the csi -0.79 "Corrosion of plaster likely". Not until it gets to more than -0.30 does it say "balanced". This is not what I have heard through searching posts.

For me, since I use softened water, the easiest thing would be to add CaCl to get the csi 'less negative' rather than mucjing with my beautiful TA I worked so hard getting down to range or pH. Still I want to be careful since getting calcium back out is no fun.

The only thing I have left to do is dump in 30-50 ppm of borates but that doesn't seem to have much of an impact on the csi.

Any practical advice for me with respect to a good target range for my plaster surface? thank you in advance :cheers:

Evan
 

257WbyMag

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Feb 23, 2008
5,061
Denton, TX
I agree. Adding a little calcium would help it out. You could also help matters by allowing your pH to rise a little, say, to 7.5 or 7.6.
 

Bama Rambler

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Jun 22, 2009
23,036
SouthWest Alabama
I agree!
But, since you have a painted pool the CSI isn't nearly as important as long as the paint covers all the cementous material and is in good shape.
 

shacke

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Jul 5, 2010
134
Philadelphia
Thanks.

What's the cheapest/best source of calcium? I assume I don't have to go to the pool store? In the summer, there won't be calcium chloride pellets in Philly - that's for melting driveway snow.
 

Txmat

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Jun 18, 2010
424
San Antonio
If you can't find any calcium chloride, you could get a small amount of Hypo at the pool store and use it the next couple of times you need to shock. I used it to shock at the beginning of the season and got my CH way too high :grrrr: Had to dump a lot of water, so if you go this way be careful.
 

duraleigh

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Apr 1, 2007
31,691
Sebring, Florida
If that was my pool, I would do nothing but swim in it. I am plain hardheaded about the use of the CSI. I never have paid the slightest attention to it and I have never had any issues. If I (and I would suggest the same philosophy to anyone else) ever begin to have scaling or leaching issues, I will then readdress where I am keeping those three parameters.

But if it ain't broke......

My thinking is if you keep your parameters (pH, TA, and CH) in their suggested ranges, you need to do nothing.

Shacke, do you have any indication of scaling or calcium precipitation in your pool?
 

shacke

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Jul 5, 2010
134
Philadelphia
duraleigh said:
If that was my pool, I would do nothing but swim in it. I am plain hardheaded about the use of the CSI. I never have paid the slightest attention to it and I have never had any issues. If I (and I would suggest the same philosophy to anyone else) ever begin to have scaling or leaching issues, I will then readdress where I am keeping those three parameters.

But if it ain't broke......

My thinking is if you keep your parameters (pH, TA, and CH) in their suggested ranges, you need to do nothing.

Shacke, do you have any indication of scaling or calcium precipitation in your pool?
I do, actually. I have white lines with the appearance that candle wax dripping and also little white spots. Figure it's gotta be calcium. I attributed it to chronically high pH that was hard to control. That's what prompted me to drop TA from 130 --> 70 and bump my CYA to reduce my SWG on time. While these steps may be enough, there is some residual scaling that I can not get off with a scrungie and I don't want to make anything worse. As it stands now, although there are white spots and streaks in areas of my dark plaster surface, I do not have to go nuclear on the scale and I am hoping it will eventually dissolve back in with good chemistry maintenance. Of course it makes me nervous adding CaCl but I do not want to risk damage to the pool surface. Thus my attention to the csi.

One thing that may be of relevance. I do use cal-hypo shock and perhaps that calcium bolus quickly precipitates at high pH levels?? I do not plan to shock every 2 weeks anymore (that was suggested by my pool servicer who I no longer listen to).

Evan
 

PaulR

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Jan 11, 2009
1,966
Cupertino, CA
Low CSI is not an emergency; it takes time. And pH is the biggest factor, so nudging that up will help.

Using cal-hypo as your normal (not shock) chlorine source for a while will slowly bring your CH up.
For each 10ppm FC from cal-hypo you get 7ppm CH.
A little playing around with Pool Calc shows a 25lb bucket of 48% cal-hypo would raise CH around 50.
However long it takes to use up the bucket, it's still worth about 50ppm CH--no need to dump it all in at once!
--paulr
 

brian987

LifeTime Supporter
When I bought my house 6 yrs ago, I realized that the pool was so pretty because they had painted it in order to avoid more costly repairs...so they hid a few thins from a naive pool purchaser. The reason I am bringing this up is because it became incredibly obvious in a short time that they had neglected the care and maintenance of the pool. I had no choice but to live with it for the first 5 yrs until I could afford to replaster.

My experience with that painted surface was tough because I received so many opinions from so many "experts". Even the pool guy I hired to replace all the equipment could not figure out why the pool walls and floor quickly acquired a brown looking algae...but all the tests showed I had no algae. After spending hundreds that summer following the advice of one pool store after another (I would try a new store when the last one gave up on what could be causing this issue), I happened to be just chatting with a friend about it at a Starbucks and a guy at the next table couldn't resist butting in with his opinion. It turned out to be just odd enough sounding to me to try his suggestion. After a similar expensive summer at his home, he was told to begin keeping his chemicals using the vinyl pool standards as a guideline. Apparently is was something about the paint they had used that was having a reaction. One more note...it was harmless to the pool or people...but very harmful to my wallet.
 

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