Sequestration or Chelation??

[mbar]

Thanks Evan!! you always make chemistry easier to understand. Most of the products claim to do the same thing - some even claim to "reduce" metals, and some claim that they will filter out. I learned from you, that they are really only sequestered, and stay in the water - unless the product does change the metal so it can fall out in a substance that can be filtered, as the metal magic claims. One of the products I looked at said that ascorbic acid was a chelator, that's where I got that from. It is so hard to believe anything they claim. So I always go back to the experience I have with my own staining. I just tried the metal magic yesterday - so far I don't see any difference. Will keep you posted.

[Jakebear]

Marie -- Evan

Thanks for the info.

The weather has been crappy here in PA so now's the time to do this --- I have a supply of Stain Free and Metal Free (Natural Chemistry). As soon as the CL gets down to between 1 & 2 ppm I'll do my thing. With "Ernesto" coming up the coast we probably won't be swimming anyway (even though there is no restriction).

I was in another Chemical reference book today --- they said the same thing you did Evan so perhaps you use the same book

I still can't get over my 0 iron and copper especially the iron. The Taylor kit doesn't lie --- Even though one of the people I work with had an explanation wanting to know what kind of Iron the test was for???? Since Taylor sells the K-1716 kit for pool water testing I figure it is for the "right kind" of iron.

[mbar]

Today I checked to see if the metal magic did anything. I did see some sediment on the bottom of the pool. The ph was low - I guess that's why metal magic wants the ph to be at 7.5 before you use it. I started at about 7.5 - 7.6, and today it was about 7.1 - I had slight staining in two spots before I put the metal magic in, and they were still there after 24 hours. I do have some ascorbic acid, and since we are having bad weather, I may use it to see if the metal magic will turn the metals that are lifted into the metal salts. My chlorine is at 10ppms, so I won't use any until it comes down - it will just waste it. I do have to say that since I had a lot of new water in the pool, and took my chlorine up to 12, I didn't get anymore stains - so at least the metal magic did work in sequestering, and maybe chelating the metals (the sediment). Jakebear, I live in PA too, so I figure now is the time to experiment with these products , while the weather is bad- I don't have much in staining though. The water is crystal clear, I'll see if it clouds after the ascorbic acid is used. I'll keep you all informed.

[waterbear]

[quote=Jakebear]Marie -- Evan

Thanks for the info.

The weather has been crappy here in PA so now's the time to do this --- I have a supply of Stain Free and Metal Free (Natural Chemistry). As soon as the CL gets down to between 1 & 2 ppm I'll do my thing. With "Ernesto" coming up the coast we probably won't be swimming anyway (even though there is no restriction).

I was in another Chemical reference book today --- they said the same thing you did Evan so perhaps you use the same book
Only reference I used was what was stored in my head....nice validation that the stuff I said was actually correct!
I still can't get over my 0 iron and copper especially the iron.
If you have stains in your pool then you probably no longer have metals dissolved in the water....they are now precipiated out as stains. The ascorbic acid (or other reducing agent) will cause the stain to convert to a form that will dissolve back into the water (It changes the oxidation state)....and the stain vanishes but now there are metals in the water! This is where the sequesterant comes in.

FYI, NaturalChemistry's Metal Free is a chelating agent (EDTA) while Proteam's Metal Magic (HEDP, a phosphonic acid derivative) is a seqesterant. EDTA has a ring structure HEDP does not.
To confuse matters even more, sequesterants are measured in how well they seqester a particular metal by their "chelation index" for that metal!
The Taylor kit doesn't lie --- Even though one of the people I work with had an explanation wanting to know what kind of Iron the test was for????
The Taylor test uses Tripyridyl-s-triazine which tests for Fe(II)...Fe is the Chemical symbol for iron. The (II) refers to it's oxidation state.
There ARE different oxidation states of iron, Fe(II) and Fe(III).
Since Taylor sells the K-1716 kit for pool water testing I figure it is for the "right kind" of iron.[
Yup!
/quote]
Isn't chemistry FUN!

[mbar]

Thanks again Evan! Now I see why metal magic will not take the stains off the surface of the pool - which it says it will. The only way that the metal magic will take the stains off somewhat is the same reason that taking the ph down to 7 and then putting in a sequesterer will work. The metal magic takes the ph down on it's own. Therefore, if the stain is there for a long time (more embeded) then you will need ascorbic acid or some other reducer to remove the stain from the surface of the pool and then any sequesterer will work. The only thing that the metal magic claims that would be different is if it really does turn the soluable metals into metal salts so they can be filtered out.

To say this is confusing is an understatement! I know what has worked, through my own experimenting on my pool, but now you are giving me the background to understanding why.

Let's see if I have this right:
You need a reducing agent (like ascorbic acid) to take the metals off the surface of the pool, putting them back into solution so they can be sequestered.

Then you need a sequestering agent or a chelator to bind with the metal to keep it in solution.
Metal sequesteres and chelators, even though they are doing different things, are acting the same way as far as the metals in the pool are concerned. Neither one is actually taking the metals out of the water.
The only way to get the metals out of the water without them staining is to find something that will turn the metals into a solid form that can be filtered out. This is what Metal Magic is claiming to do.

I am going to try my experiment with the ascorbic acid to see if the removed stain - I never thought I would say I wish I had more stain! - will get turned into metal salt with the metal magic that is in the water, so it can be filtered out.

This morning there was some more sediment in the bottome of the pool - hopefully it is the metal magic working to change the metals that are in solution into metal salts so they can be filtered out, or vacuumed out.

I will try this again in the spring when I open the pool. It will be easier to test if I let some stains form, but it will worth it to find out how to get the metal out!

I will keep you all posted

[waterbear]

Thanks again Evan! Now I see why metal magic will not take the stains off the surface of the pool - which it says it will. The only way that the metal magic will take the stains off somewhat is the same reason that taking the ph down to 7 and then putting in a sequesterer will work. The metal magic takes the ph down on it's own. Therefore, if the stain is there for a long time (more embeded) then you will need ascorbic acid or some other reducer to remove the stain from the surface of the pool and then any sequesterer will work. The only thing that the metal magic claims that would be different is if it really does turn the soluable metals into metal salts so they can be filtered out.

To say this is confusing is an understatement! I know what has worked, through my own experimenting on my pool, but now you are giving me the background to understanding why.

Let's see if I have this right:
You need a reducing agent (like ascorbic acid) to take the metals off the surface of the pool, putting them back into solution so they can be sequestered.

Then you need a sequestering agent or a chelator to bind with the metal to keep it in solution.
Metal sequesteres and chelators, even though they are doing different things, are acting the same way as far as the metals in the pool are concerned. Neither one is actually taking the metals out of the water.
The only way to get the metals out of the water without them staining is to find something that will turn the metals into a solid form that can be filtered out. This is what Metal Magic is claiming to do.

I am going to try my experiment with the ascorbic acid to see if the removed stain - I never thought I would say I wish I had more stain! - will get turned into metal salt with the metal magic that is in the water, so it can be filtered out.

This morning there was some more sediment in the bottome of the pool - hopefully it is the metal magic working to change the metals that are in solution into metal salts so they can be filtered out, or vacuumed out.

I will try this again in the spring when I open the pool. It will be easier to test if I let some stains form, but it will worth it to find out how to get the metal out!

I will keep you all posted

To the best of my understandintg you have it right! As far as Metal Magic goes....they might have a reducing agent in it as well as a seqesterant. Can't tell from the MSDS.

[doggie]

I hope nobody minds me butting in here. I was wondering which would be a better product to use to remove any potential metals from my fill water when we refill after the new liner is installed. I have some of both GLB's Sequa-Sol and also Natural Chemistry's Metal Free.

Would one be better than the other on a fresh fill? Or should I use them both before I close for the winter? (not at once of course)

I want to make sure and get all the metals before they have a chance to do anything. I don't know the metal content, but it seems most of your opinions is more is better when it comes to preventing metal stains. This will be city water by the way.


Thanks.

[mbar]

I have used both sequasol and metal free. They are both good, so it doesn't matter which you use. I would add a good dose right after your fill - a little more than the bottle says. You will not have to do anything else when you close. I have already closed with stains and opened to a stain free pool - I don't know why, I can only guess, so don't worry about adding any sequesterer when you close. I would save the chemicals for next year when you open. Next year when you open, before putting anything else in the water add the sequesterer. This way any metals the were introduced over the winter or with your fill water will be taken care of. Then you only need to add it if you see any stain starting to form. If you see stain start, take your ph down to 7 - 7.2 and add sequesterer - it should lift the stains before they settle. Feel free to ask any questions you have

[waterbear]

I hope nobody minds me butting in here. I was wondering which would be a better product to use to remove any potential metals from my fill water when we refill after the new liner is installed. I have some of both GLB's Sequa-Sol and also Natural Chemistry's Metal Free.

Would one be better than the other on a fresh fill? Or should I use them both before I close for the winter? (not at once of course)

I want to make sure and get all the metals before they have a chance to do anything. I don't know the metal content, but it seems most of your opinions is more is better when it comes to preventing metal stains. This will be city water by the way.


Thanks.

First thing I would do is get the water tested for metals...if there are non present then don't add either one....If it ain't broken don't fix it!

[Jakebear]

OK Marie ---- How long should I expect it to take (getting the chlorine back up)??

I've read to bring it up slowly (1ppm per day) but at this rate it'll be next summer

Since I did the Ascorbic Acid and the Chelator, I have added Chlorine 8 times, and still the cl is <1ppm after a few hours. I suspect it is still consuming the Ascorbic Acid but after 3 days --- Enough already

One good thing --- We had 4.06 inches of rain, so my CYA is now near 40 So I should be able to go down a notch on Ben's BG Chart. I'm still shooting for between 4 & 6 just to keep it on the high side.

For those who care:
Water Temp 68 BRRRRRRR
pH 7.5 by titration
FC .4 ppm (FAS-DPD)
TC .6 ppm (FAS-DPD)
CC .2 ppm (FAS-DPD)
TA 80 ppm (by titration)
CH 240 ppm (by titration)
Phosphates <50 ppm
CYA = ~43 (turbidimetric)