Pool Math Query

[Sid/]

I have question on the "Pool Math" app. The "pool math" app states that the SUGGESTED RANGE for "CSI" is between "-0.60 to 0.60" and then states at the bottom of the CSI that "Less than -0.3 suggests potential to become corrosive to plaster, tile, stone and pebble pools." My question is shouldn't if a person's pool be within the "SUGGESTED RANGE" that that range should not cause any plaster damage to a pool??

 

[JoyfulNoise]

Not really. All the CSI number tells you is that there is a "potential" to scale or corrode (etch) but it tells you nothing about the rate at which that will happen. Even with water at a CSI of -0.6, it would take months of constant low CSI to start to cause any noticeable damage. Likewise, at +0.6, scaling can occur, but it's going to take a long time before one sees anything. However, there are times when a person might need to add chemicals that either raise or lower the pH (pH tends to have the biggest impact on CSI) and so their water might go into one of those high ranges for a short time and that's totally ok. Sometimes when I add acid to lower my pH, my CSI goes below -0.4; again, that's ok because I know in less than 24 hours my pH will rise up a bit and my CSI will be in the "ok" zone.

So the the way the ranges are established and how the wording in the advice is constructed is to simply be informative but not cause a panic.

 

[Sid/]

So if I keep the Pool app CSI in the suggested range of -0.60 to 0.60 according to the Pool App" for an extended period of time I could develop "a potential to become corrosive to plaster, tile, stone, and pebble stone." I guess my suggestion would be maybe add a time frame to these CSI numbers or maybe change these numbers that would not allow ANY damage to your plaster at any given length of time by CSI.

 

[JoyfulNoise]

Neither of those options are practical because the time it takes for damage to occur can vary depending on the conditions involved and is somewhat unique to a pools surface type. There's no way too know beforehand how much time it will take to scale or corrode based simply on the CSI value and there's no simple or easy way to calculate those things. Restricting the range to a point where it "can never happen" is unrealistic because there are times when deviating from the range can happen and it's ok to do so. The PoolMath App is a great tool but, it's just a tool. No one should ever blindly follow what PoolMath says and they should leverage the deep knowledge base of this online forum when numbers or concepts appear confusing...an App can't do that (well, not until @Leebo gets Siri/"Hey Google" functionality working on the App).

The thing to keep in mind is this - we're not cooking up rocket fuel here, it's pool water; it's ok to be a live within the ranges and deviate here and there for a time. Most pool damage occurs from long-term neglect, not transient mistakes. TFP teaches people to be mindful of their water chemistry and act preventatively and that solves 99.9% of most pool problems.

 

[Sid/]

Thanks Joyful,
Guess from my military days that accuracy and timing was life and death. Guess I'm still trying to deal with not everything has to be so precise in the civilian world...Even with all that said "-0.60 to 0.60 is the suggested range, and the app tells me that I can be within that range and still have problems with my pool. Just not convinced yet that the numbers should not be changed on the APP. I'm just making a suggestion on the "Pool Math" app should read -0.30 to 0.60 to better reflect the possibility of "Less than -0.3 suggests potential to become corrosive to plaster, tile, stone and pebble polls." Guess what I am saying that "-0.60 should read -0.30". Hopefully that makes sense.

 

[kimkats]

I will put in a ping for the guy who is in charge of this @Leebo to make sure he see this.

 

[Texas Splash]

The thing to keep in mind is this - we're not cooking up rocket fuel here,

What? I've been putting that in my resumes all this time.

 

[Leebo]

Sid,
If I may ask..........what are your current test results??

 

[Sid/]

Sid,
If I may ask..........what are your current test results??

Leebo
Here are the test results you requested.
CL - 5.0
PH - 7.6
TA - 80
CH - 250
CYA - 40
Water Temp - 44 F
CSI = -0.48

 

[Leebo]

Sorry things kinda dropped off Sid.

With your water temp being 44° any damage that in theory could occur will take forever to happen. Cold water slows down everything so my suggestion would be to let your pH to slightly drift up to 7.8 or so and enjoy some hot coco.

As for the levels and the wording. CSI is one of those things that’s easy to get lost in. It’s easy to drive yourself nutty trying to hit an exact number. Bad thing is, there is no perfect number.

 

[Sid/]

Leebo,
Yeah I have been letting the Ph drift up to near 8 and then give a dose of acid to get it back down to 7.6 or so. Thanks for your response. Going for the hot coco now.