Sequestration or Chelation??

[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

[Jakebear]

WOW --- this is great information and I do (almost) understand it.

Evan -- I've learned more chemistry since looking at this forum than I did at Brevard Engineering College (now FIT) in Melbourne back in the 60s.

Marie -- Keep the info coming about Metal Magic --- I'd just as soon have it settle so the robot can gobble it up and I can get rid of it. I do add quite a bit of water from the well so I guess the chelator or sequestrant will be a regular around here.

The free Cl has nearly quit dropping (2.8ppm) so I'm still waiting to add the Ascorbic Acid. Since the CYA is ~50 it could take a while based on Richard's half life explanations. Might have to add some sodium thiosulphate to lower it the rest of the way (Target = 1-2ppm)

Marie --- I'll have to look you up next time I make the run from Mahanoy to Shamokin. With all that coal leeche no wonder you get stains. Do you have to fight low pH too?

[mbar]

Mahanoy to Shamokin!!! We are neighbors Yep, the coal regions. I used to fight low ph, but this year for some reason my ph keeps rising It may be because it has been dry and I haven't used many trichlor pucks this year. I used to use them to keep the ph low so I wouldn't get stains. This year I didn't have any problem with stains so I have been just using bleach. I didn't check it today, but it probably is low from all the rain. What town are you from?

[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]

Stain Free followed up with Metal Free (both Natural Chemistry products) per the directions on the bottle. It was dark till the metal free went in so I don't know if it got cloudy or not. I do know that the stain disappeared almost immediately when the Ascorbic acid hit the water.
We'll see the results in the morning.

The jug of Metal Free said to run the pump 72 hours then change DE (in my case) but I'm wondering how long I should keep the Cl down??? It does not say --- with the rain that we are supposed to get, I'm a bit nervous with it down around 1.5 ppm and CYA ~50. Any thoughts?? Phosphates are <100 so there isn't anything for algae to eat.

[mbar]

After 24 hours and if the stain is gone, you can start to balance the water. Your ph and alkalinity will be probably be low after the ascorbic acid, and you will probably have trouble keeping chlorine in the water. You can get your ph up to 7.2 and then start to add the bleach, add enough to take it up about 2ppms, waiting a little while and adding more until you reach about 4 or 5 for your cya. If you start to see stain forming, make sure your ph is no higher than 7.2 and add more metal free. You should be fine. Just don't shock for at least a week, maybe 2. You can keep your chlorine at the high side for your cya which at 50 would be 6-8ppms, but I wouldn't go higher for the 2 weeks. Feel free to ask any questions you have, good luck

[Jakebear]

The pH was ok this morning (7.5) TA down to 90 but FCl was 0.0 Added a bit of 6% (diluted first in pool water) to bring it up to ~1ppm and threw the robot in to keep stuff stirred up. The water is crystal clear and no apparent sediment on the seams of the liner where it always collects.

Still no rain but they are predicting 4-6 inches around here --- We'll see. I want to get CYA down to ~20 for winter then see where it needs to be for operations next year.

I'll keep you posted on the stains removal process.

[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)