TDS, IRON, COPPER

Themacdadt

Well-known member
Sep 11, 2013
163
Cocoa, fl
All my levels are where they should be according to tfpc. My question is....and I know tds means nothing but my tds level is 5000 So I still don’t need to worry about that correct?

iron is .2 Any worries there? And does sequesterants alter the test?

copper is 0. So I know there is no worries there.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
16,126
Northern NJ
All my levels are where they should be according to tfpc. My question is....and I know tds means nothing but my tds level is 5000 So I still don’t need to worry about that correct?
Correct.


iron is .2 Any worries there? And does sequesterants alter the test?
Iron bound to the sequestrant does not show in water test. Water test only shows soluble iron.

Are you using a sequestrant?

Sequestrant - Further Reading

copper is 0. So I know there is no worries there.
(y)
 

Themacdadt

Well-known member
Sep 11, 2013
163
Cocoa, fl
And just some info, when I added the sequesterant my water turned pretty blue. After a while it turned back to original color of a little greenish hue.
 

Themacdadt

Well-known member
Sep 11, 2013
163
Cocoa, fl
What would be a level of iron in the pool where a drain and refill would be required?

i feel sequesterants are a band aid to the problem. I want to get rid of the underlying problem to where sequesterants are not utilized.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,228
Pleasanton, CA
TDS is made up of primarily salt, calcium and magnesium (phosphates and nitrates too). So do you know what your actual salt and CH levels are?

If the true salt level is close to 5000 ppm, then your cell may be failing if it is reporting lower salt levels.
 
Last edited:

Themacdadt

Well-known member
Sep 11, 2013
163
Cocoa, fl
TDS is made up of primarily salt, calcium and magnesium (phosphates and nitrates too). So do you know what your actual salt and CH levels are?

If the true salt level is close to 5000 ppm, then your cell may be failing if it is reporting lower salt levels.
salt is 3200, CH IS 300
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
16,126
Northern NJ
What would be a level of iron in the pool where a drain and refill would be required?

The easiest rule of thumb for metal concentrations is you want them to be as close to 0 as possible. Typically speaking, iron in concentrations greater than 0.3ppm will start to scale out of solution and form brown water (tea colored) or yellow stains on pool surfaces.

i feel sequesterants are a band aid to the problem. I want to get rid of the underlying problem to where sequesterants are not utilized.
Agreed. Once you get on sequestrants you need to add them regularly as they degrade.

Here is an example of an iron filter on pool fill water...

 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,228
Pleasanton, CA
Then there is a very large (1500 ppm) amount of TDS unaccounted for. Although we generally tell people to ignore TDS, that is only for the case where TDS is made up of normal stuff in pools (salt, calcium, etc.). Salt is usually the largest component with calcium being next. So either the TDS test is in error or you have quite a bit of a foreign substance in the pool. Something I would investigate.
 

Themacdadt

Well-known member
Sep 11, 2013
163
Cocoa, fl
Then there is a very large (1500 ppm) amount of TDS unaccounted for. Although we generally tell people to ignore TDS, that is only for the case where TDS is made up of normal stuff in pools (salt, calcium, etc.). Salt is usually the largest component with calcium being next. So either the TDS test is in error or you have quite a bit of a foreign substance in the pool. Something I would investigate.
Had the tds tested twice at 2 different sources. Same day one was 4500 one was 5000
 

JamesW

TFP Expert
Mar 2, 2011
18,479
TDS is not a valid measurement because it reports in units of "4-4-2".

A dual meter like the Myron L PoolMeter has two different settings.

One setting is used for salt water and the other is used for "Natural" water, which is simulated by a 4-4-2 solution.

Using the meter set to the TDS setting is not going to give a correct reading for salt water. It's a common mistake that pool stores make. The PoolMeter should not have a TDS setting. It's a stupid design.

Here's a chart that shows how salt water and TDS Natural water compare at the same conductivity measured in microsiemens.

As you can see, the salt water at 3200 had the same conductivity as Natural water at 5000, which accounts for the difference.


 

JamesW

TFP Expert
Mar 2, 2011
18,479
The 442 Standard Solutions consist of the following salt ratios: 40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride.

Unless your water makeup matches this, which it doesn't, the TDS reading is meaningless.

What usually happens is the pool store will set the meter to salinity and take a reading and then to TDS and take a reading and report both numbers.

But, think about it, how can the conductivity meter isolate just the salt in the first reading?

It can't. It just measures conductivity in both tests, which has to be exactly the same reading.

The only difference is the multiplier used in each setting.

When testing a salt pool, only the salt multiplier is valid.
 
Last edited:

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
13,228
Pleasanton, CA
I guess I was assuming they would measure it with a proper calibration solution. Most of the meters I see at pool stores have only a TDS measurement like my meter. However, you do have to calibrate it with a salt solution and preferably close to the measurement point. If fact, my meter's instructions were very specific about using a salt solution calibration as they are marketed for residential use. I think the meters you have shown are more applicable to the boiler industry than the pool industry. If they are using those meters, then they should have read the manual. But it would explain the difference.
 

JamesW

TFP Expert
Mar 2, 2011
18,479
A conductivity meter only measures conductivity, which is affected by all charged particles in the water.

Once you get the conductivity reading, you need to know the makeup of the tds so that you can select the correct conversion factor from conductivity to tds.

The meters used for pool use are usually salinity and not TDS or they are dual use.

Part of the confusion is that salt is tds.

A meter measuring "salt" or salinity assumes that all tds is sodium chloride even though there are other components.

A meter measuring "TDS" assumes a 442 mixture, which is not suitable for pool water. A TDS setting measures conductivity and then uses the TDS conversion chart, which is different from the salinity conversion chart.

Calibrating a TDS meter with a salt standard solution will not be accurate at any reading except the reference point.

When measuring salinity, a meter set to salinity is the correct choice.

The PoolMeter is used by pool stores and is designed for pool use as evidenced by the name.

They indicate that the meter can differentiate between salinity and TDS, which is nonsense.

If you wrote to the MyronL company and asked them how the meter can differentiate between salinity and TDS, they would realize that they made a mistake and they would have to rewrite the literature.

What meter do you have?
 
Last edited:

JamesW

TFP Expert
Mar 2, 2011
18,479


This is the chart showing salinity and TDS in ppm vs conductivity.

For example, if the meter measures the conductivity at 6,000 microsiemens/cm, the conversion chart says 3,200 ppm if the water contains all salt and 4,900 ppm if the water contains a mixture consistent with 442 or Natural water.

Since the pool water is not consistent with 442 makeup, using a TDS meter and TDS (442) chart is not appropriate even if you use a salt standard solution.
 
Last edited: