Water Chemistry Help

Mdragger88

Bronze Supporter
Jun 1, 2018
3,135
Hernando, Ms
Pool Size
26000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
Our local aquatic center has a fleet of dolphins. There may be some rule about using them with people in the pool but other than that I can’t imagine there would be an issue. But hey, I’m in Mississippi so there’s really no telling 😜
 
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JamesW

TFP Expert
Mar 2, 2011
28,209
Salt only leaves the pool when you lose water other than evaporation, such as backwashing.

So, it depends on the amount of water that is lost.

The original amount assumes a starting salinity of 1,000 ppm from past chlorine use.

If you start with a fresh fill, then the amount will be more.

You might need maybe 10 bags a season as an estimate.

I don’t know of any rules against having an automatic cleaner.

I don’t think that I would have the cleaner in while people swim.

Maybe put it in at night or when the pool is otherwise closed.
 

JPMorgan

Well-known member
May 22, 2018
400
Elmhurst, IL
Pool Size
20000
Surface
Plaster
Chlorine
Liquid Chlorine
So..... just wondering (never got comments on this question above).... how much water would need to be drained from a 60k pool to reduce CYA from 180 to 30-40. 50k???
 

PoolStored

Gold Supporter
Jun 24, 2021
566
Ashtabula, OH
Pool Size
31000
Surface
Vinyl
Chlorine
Liquid Chlorine
So..... just wondering (never got comments on this question above).... how much water would need to be drained from a 60k pool to reduce CYA from 180 to 30-40. 50k???
It is a straight 1:1. 130 / 180 = 72% or 43k replace gets you to 50 CYA.
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
29,060
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
So..... just wondering (never got comments on this question above).... how much water would need to be drained from a 60k pool to reduce CYA from 180 to 30-40. 50k???

Every 6,000 gallons drained reduces CYA by 18.
 
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JPMorgan

Well-known member
May 22, 2018
400
Elmhurst, IL
Pool Size
20000
Surface
Plaster
Chlorine
Liquid Chlorine
Thanks for the assistance on how to figure out how much water to drain to reduce CYA. I forgot that was available in Pool Math, as I have been mainly using the App lately and it does not do that calculation for you. I took a couple of photos of the bottom of the pool. I'm assuming that is algae that I'm seeing at the bottom. Shouldn't CC be >0 if algae is present?

Last test results:
FC 1.5
CC 0
pH 7.0 Could be even lower.... how do you get a reading below 7.0?
TA 70 (did not retest)
CH 160 (did not retest)
CYA 180
CSI -1.27

How is CC at 0 when FC is 1.5 and CYA is off the charts?

IMG_2209 (1).jpg

IMG_2208.jpg
 

Mdragger88

Bronze Supporter
Jun 1, 2018
3,135
Hernando, Ms
Pool Size
26000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
The absence of cc’s is not a sure fire indicator that algae isn’t present
The presence of cc’s is an indicator that something is being consumed by fc - not necessarily algae.
An Overnight Chlorine Loss Test is the way to determine if organics are present.
Fc should be at target levels for this test.
The fc is extremely low & if that’s not algae I would be surprised.
 
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JamesW

TFP Expert
Mar 2, 2011
28,209
If it brushes off easily, then it is likely to be algae.

If it does not brush off easily, then it is probably iron stains.

Throw a vitamin C tab on the spot to confirm iron.
 

JPMorgan

Well-known member
May 22, 2018
400
Elmhurst, IL
Pool Size
20000
Surface
Plaster
Chlorine
Liquid Chlorine
If it brushes off easily, then it is likely to be algae.

If it does not brush off easily, then it is probably iron stains.

Throw a vitamin C tab on the spot to confirm iron.
Doubt it is iron. They would be on the same Lake Michigan water as my home pool and I have never had iron stains. Could iron stains come from an algaecide or other additives they may be using to try to treat the algae?
 

JPMorgan

Well-known member
May 22, 2018
400
Elmhurst, IL
Pool Size
20000
Surface
Plaster
Chlorine
Liquid Chlorine
............... and to think WE helped paint that pool, in theory at least. Congrats JP !!!
:) You absolutely did help paint my pool! I’m turning that one over to my daughter and son-in-law now (though I know they will be looking for my expertise in caring for the pool) and starting to focus on this condo pool. We’re moved into the condo now and I’m meeting the guy who has been taking care of the pool this morning. Should be interesting. I’m going to take a gentle, non-threatening, educational approach and hope that they will accept the help. I know they can have a better pool if they adopt TFP methods. We’ll see how it goes and I’ll keep you posted.
BTW... painted pool still looks great after first season. We’ll see how well it holds up next year.
 

Newdude

Gold Supporter
TFP Guide
Jun 16, 2019
11,173
NY
Good luck with the new endeavors. Best wishes moving in too. I moved last year and there is still some lingering PTSD issues. :ROFLMAO:

It gets a little better every day.
 

JPMorgan

Well-known member
May 22, 2018
400
Elmhurst, IL
Pool Size
20000
Surface
Plaster
Chlorine
Liquid Chlorine
Meeting with HOA President and Pool Company tomorrow. Little has changed in water chemistry at the pool.... pH still low, CYA off the charts and algae present in the pool. Saw a person from the pool company at the pool on Monday, but did not get a chance to talk with him. Checked pH later in the day and saw no change, so he came and went without addressing that. Pool was brushed, but algae was present again the following day. I assume this is due to high CYA and ineffective chlorine dosing. Will algae stain plaster? Note the brushed areas in the photos below. Algae has been brushed away partially, but the brushed areas still have stains. What will lthe consequences be if they close the pool with CYA at >180 and pH at 7.0? I expect to be told tomorrow that they plan to close the pool as is and then drain and power wash in the spring. I'm guessing pool will be full of algae then, even if they raise FC to 10 and dump a bunch of winter algaecide in the pool before closing. One final question (for now). How do you test for pH below 7 since the color scale only goes down to 7.0?

IMG_2250.jpegIMG_2251.jpeg
 

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