LSI vs CSI

Propbndr

LifeTime Supporter
Mar 26, 2015
329
Charles City, Va
What is the difference between the two? Are they interchangeable? Pool Math calculates CSI, I guess for those owners who have an other than vinyl pool surface. Equipment manufacture’s use LSI in their levels for a “balanced” pool chemistry. I read the Langelier and Calcite Saturation Indices (LSI and CSI) thread. As a non-chemistry type, it was as clear as mud to me.
 
I'm with you , a lot of this stuff goes over my head....

LSI was originally developed to deal with corrosion and scaling in metal pipes (boiler-making). CSI was developed with pools in mind.

But, when you come dow to it they both point you in the same general direction. Plus, if you keep your pool balanced according to the TFP - Recommended Levels you rally don't need to worry about it too much. It's folks in areas which high calcium or some other anomaly that makes them work outside the recommendations that CSI becomes something to watch.
 
My SWG salt level detector went bad, causing the system to shut down due to what it says are low salt levels. Based on conversations, I think the manufacturer may try to get out of a warrantee repair because I said I tracked the CSI instead of the LSI. They are also harping on phosphate and TA, and CH levels not being in their specs

FC - 33
CC - .5
PH - 7.2
CYA - 85 (a little high)
TA - 80
CH - 50
Phosphates (when pool was green)- 500,000 ppb (through the roof)
Copper - .8 ppm
Iron - 0 ppm
Temp - 85

I opened late too a swamp (my screw up). After completing my SLAM, I’ll measure the phosphates again to see where I stand. At this point I don’t know if I will worry with it unless it causes me to use too much FC trying to keep up with the nasties. As I have a vinyl pool, I don’t really worry about CSI because it never gets to a level where I have to worry about corrosion.
 
My SWG salt level detector went bad, causing the system to shut down due to what it says are low salt levels. Based on conversations, I think the manufacturer may try to get out of a warrantee repair because I said I tracked the CSI instead of the LSI. They are also harping on phosphate and TA, and CH levels not being in their specs

FC - 33
CC - .5
PH - 7.2
CYA - 85 (a little high)
TA - 80
CH - 50
Phosphates (when pool was green)- 500,000 ppb (through the roof)
Copper - .8 ppm
Iron - 0 ppm
Temp - 85

I opened late too a swamp (my screw up). After completing my SLAM, I’ll measure the phosphates again to see where I stand. At this point I don’t know if I will worry with it unless it causes me to use too much FC trying to keep up with the nasties. As I have a vinyl pool, I don’t worry about CSI because it never gets to a level where I have to worry about corrosion.

To be honest, I never test for phosphates. In a properly chlorinated pool they are meaningless. It's just a way for the pool store to sell you phosphate remover. The theory in removing them is - they are algae food. But, in the absence of algae, what does it matter. Someone said it best, what good is a beautiful buffet full of all the food you like if the room is filled with chlorine gas. You can't go in to eat the food.....
 
To be honest, I never test for phosphates. In a prperly chlorinated pool they are meaningless. It's just a way for the pool store to sell you phosphate remover.

What you say is true. I suspect that my level is super high because algae has captured phosphates within the cells. That may cause a false high. Once I have the algae gone it may drop to almost nothing. It costs me nothing to get it tested and will allow me to prove or disprove my suspicions.

In hind sight, the “newbie” technician actually said that high phosphate and low CH levels can cause plating on the cell plates. It was all I could do to keep from calling her an idiot.
 
Well, you have the best test kit going, why bother taking them any more water.....
The only reason I took and will take another is for printed, third party, documentation of test results.
I went to the company that originally installed the pool. Believe it or not, their prices for everything are almost the same as Lowe’s, Walmart, etc. and they give a 10% veteran discount.
 
The only reason I took and will take another is for printed, third party, documentation of test results.
I went to the company that originally installed the pool. Believe it or not, their prices for everything are almost the same as Lowe’s, Walmart, etc. and they give a 10% veteran discount.
Yea, "my" pool store sells muratic acid for less than the big box stores, so that is all I get there. After listening to the "less than educated" advice on multiple occasions I just stopped taking water. When the teenager told me that I needed my TA at 120 and that it would make my pH more stable (I keep it at 60) I just stopped.

I had a different pool store ask me why I used liquid chlorine. When I mentioned CYA the woman (actually the store manager) told me that liquid has stabilizer in it, I should save myself the hassle and use tabs......

What the pool industry does not understand is that the internet is changing the industry around them. My favorite story is about my pool light. When I bought the house with the pool along with high CYA my pool light was not working. I could get a new bulb from Amazon for $19, but heck I'm part of that immediate gratification society as much as the next guy. I went down to the pool store and there was the same bulb, $39. I talked with the manager. I didn't want them to match the price, they have to keep the lights on - just be a little more reasonable. The manager gave me two choices, take it or leave it. I left it. I can wait 2 days.....
 
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