1. ## Winter Tips?

So I have a question. Have seen several posts here over the past few days that state they have never calculated CSI. It was my understanding that's a rather critical index to know. Perhaps that's only true for the more newbies amongst us?

Playing with Pool Math as the temperature goes down, shows that CSI can quickly get into a corrosive state if you hold the other params the same as summer values.

The differences can be significant. Holding other params in check, at 45 degree water, a pH of 7.6, a normal summertime value leads to a CSI that is -.62, corrosive, while allowing it sit at 8.0 raises it up to -0.24, which is stated to be balanced.

So what do people that don't close their pool do during the winter? Do you let pH and TA take on higher values so that CSI doesn't get into the corrosive range? If you don't test for CSI, do you have different levels you aim for in the winter vs. the summer?

Let me be clear. I am not finding fault with other posts and other methodology. Those posters have far more knowledge and experience than I do. Maybe they close their pools and don't have to worry about this. I don't know. I'm just stating that for _me_, the CSI value has been important to look at in helping to balance the pool and I am not sure how to continue to do that as the temperature drops without raising some params (like pH) to compensate for the temperature drop.

2. ## Re: Winter Tips?

You've got it figured. You can't control the temperature so you have to fiddle with something else. Let pH climb a bit or raise the TA with baking soda.

3. ## Re: Winter Tips?

Nearly everyone should completely ignore CSI. It is only if it is impossible for you to follow our level recommendations, for example because of high TA or high CA fill water, that you really need to start watching CSI.

When a pool is winterized, the PH will go up as the temperature falls, nearly exactly canceling out the CSI change. So anyone who winterizes can ignore this issue.

If you keep the pool open year round, and the water temperature goes down below roughly 50 degrees, you do need to know to let the PH come up rather than maintaining it at normal levels. If you are also prone to metal staining this can be problematic and different measures may be required.

4. ## Re: Winter Tips?

Originally Posted by JasonLion
If you keep the pool open year round, and the water temperature goes down below roughly 50 degrees, you do need to know to let the PH come up rather than maintaining it at normal levels. If you are also prone to metal staining this can be problematic and different measures may be required.
Is that in pool school somewhere and I missed it (let pH rise in winter)? The thing that clued me in to figuring it out was looking at CSI and figuring out the impacts of various parameters. I can certainly see why if you close your pool and maintain TFP levels during the summer (which automatically put you in the right CSI range), that factor doesn't need to be on your radar screen.

5. ## Re: Winter Tips?

Hi again bob! haha! yeah, its me!

I think the subject of CSI is very important, such as you do. For some, it's somewhat of a confusing subject and requires a higher level of understanding of the chemistry involved. I think most of us would agree, that CSI is pretty much considered an 'advanced' parameter.

For a lot of new folks, it may cloud the water (pun intended), for people who for the immediate near term, need to learn just the basic care. We try to keep it simple, but there is certainly more advanced topics which aren't specifically covered in pool school.
It seems you have a pretty good handle on it though.

There are deeper discussions about CSI in 'The Deep End' forum, and "Chemistry 201" that are of great interest and provide a bit more insight of it for you.

6. ## Re: Winter Tips?

When the water is cold I let the PH go up. It usually never goes to 8.2 or higher and my CSI is usually near 0 wherever it decides to level out, so like Jason said, it cancels it out.

7. ## Re: Winter Tips?

Originally Posted by Divin Dave
Hi again bob! haha! yeah, its me!

I think the subject of CSI is very important, such as you do. For some, it's somewhat of a confusing subject and requires a higher level of understanding of the chemistry involved. I think most of us would agree, that CSI is pretty much considered an 'advanced' parameter.

For a lot of new folks, it may cloud the water (pun intended), for people who for the immediate near term, need to learn just the basic care. We try to keep it simple, but there is certainly more advanced topics which aren't specifically covered in pool school.
It seems you have a pretty good handle on it though.

There are deeper discussions about CSI in 'The Deep End' forum, and "Chemistry 201" that are of great interest and provide a bit more insight of it for you.
Hi Dave...

To *ME*, I don't consider it an advanced parameter. It's an index; a combination of individual parameters. For *ME* it helps to determine trade-offs and balances and those parameters that influence chemistry more than others. If there are 4 things wrong, which should I tackle first to effect the most change, etc. Things like that. Looking at effect of temperature and how you have to compensate.

Did I mention this is solely how *I* view it.

As always, YMMV. No disrespect intended. No animals were harmed during the construction of this message. All rights intact. No employees or their families are eligible for the grand prize.

9. ## Re: Winter Tips?

Originally Posted by zethacat
Hmmm...not sure I understand that emoticon...

10. ## Re: Winter Tips?

Originally Posted by eqbob
Hmmm...not sure I understand that emoticon...
Thats what algae looks like when chlorine attacks it.

11. ## Re: Winter Tips?

Hmmm....so now I'm algae <G>

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