Sequestration or Chelation??

[mbar]

Glad to hear all is well Don't worry, if you get any stains back next year, you will know how to get rid of them before they become hard to remove. The key is to keep the water balanced with the ph on the low side, and keep up with the chlorine so you don't have to shock very often. Plus keeping the sequesterer in the water at all times. It is the first thing I put in the water when I open in the spring - sequesterer goes in as soon as the cover comes off - then chlorine. Tomorrow I close the pool, I am sad

[Jakebear]

Hello again,

Well, nearly a year has past and the same stain is back. I have used a chelating agent (Metal Free [Natural Chemistry]) religiously. The pool is sparkling and the Chemistry is great (see below), I just don't understand why this stain keeps coming back??

The pool gets cleaned 3 or 4 times a week with the Aquabot (it's never dirty -- mostly the pool gets cleaned -- because ---) so if something would drop out, it would get gobbled up before it could go (dissolve) back into the water.

Since we are full BBB with bleach injection everything has been very stable, and the water has been great. Not even any good reason to shock.

My only thought was that I do not change the DE filter unless there is a back pressure situation and this has only occurred twice since I opened the pool.

Perhaps I need to change to a sequesterant?? What do you think?? Any recommendations??

H2O Temp = 86
FC = 3.6
CC = 0
CYA = 28
Phosphates <50 PPB
pH = 7.6
TA = 90

[mbar]

This is only a theory on my part. I used to get a lot more staining when my cya was under 40. I now keep my cya at 50 or a little higher. One year I experimented with keeping it at about 30 and had a lot of stains, Last year I kept it at about 50 and had very little staining. The lower cya may make the chlorine eat up the sequestering agent faster. I have been using Proteams Metal Magic, and it seems to work really well. If I see any stain starting to form, I add it and it takes it away. I also have been keeping my ph low - not higher than 7.4, with alkalinity no higher than 90. I also used a clarifier that Waterbear reccommended - Seaklear natural clarifier, here is a link: http://www.poolgeek.com/SeaKlear-Nat...ools-p/skq.htm
I am not sure which it is, or the combination of all three, but my pool has not had much staining at all this year after the initial ascorbic acid treatment I had to do at the beginning of the year after opening to a green swamp and having to have my chlorine levels at shock levels for 2 weeks I am working with a friend of mine that has had a lot of pool problems, algae and staining I am going to try using this theory on her pool too. I will keep you informed.

From your water chemistry, everything seems to be in order. I would try to raise the cya up a bit and see if it helps keep the sequestering agent in the water longer. Maybe even try the SeaKlear. I don't think there is much difference between the good sequestering agents. So it is up to you. I do like the Proteam Metal Magic, but I also liked Jack's Magic and Sequasol too. I have heard good things about getting a metal out from Ace Hardware that is cheaper too. I can't remember the name right now. I would suggest taking the ph down and adding the sequestering agent, to see if that will do the trick by itself. If not, a little ascorbic acid will do it - I know it is a pain, but you may not need a lot. I am still experimenting to see what works best, that is why it's great that you let me know works well for you, so we can put them in the "stain eliminator" reference

[Jakebear]

Hi Marie,

Thanks for the reply. I was looking at the Metal Magic web site, this product seems a lot cheaper than the Natural Chemistry. Just wondering, did you use the SeaKlear because the Metal Magic made things cloudy?

I've been procrastinating since things are finally nice and warm and the stain is still "minor" (not visible except the skimmer boxes & not the steps yet) and I don't want to lose a day of swimming right now. Also, I did not see anything about phosphates on the Metal Magic label either. I'm still investigating.

What bugs me is where this is coming from since the K-1716 Iron Kit from Taylor shows 0 ppm, same with copper using the K-1730 kit (0 ppm) (both samples of my make-up water). What else is there? Or better yet how do I test for it?

[waterbear]

All HEDP based seqesterants will cause phosphate levels to rise. Don't worry about the phosphates. It's really a scam. Chitosan based clarifiers (like SeaKlear) have some sequestering abiltiy but not as much as a HEDP based product. The Ace product is O-Ace-Sis Metal Out Plus.

[Jakebear]

Hi Evan,

Thanks for weighing in. I'll look for a Ace with a pool section. Most everything in my area are TV or Do it Best, but around work there are a few.

Any SWAG why I don't show levels (Metals) when I test my make-up water (K-1716 & K-1730 [both Taylor])??

[mbar]

Thanks Evan I am wrinting that name down now. As far as the metals testing in the water, I never have metals, but I get stains. When the metals have fallen out, or are sequestered, the test will not show metals. So, you would have to get it at the perfect time to have the metals show up on the test - unless you test your fill water - that will show metals (if that is where they are coming from). Metals can get in the water in so many ways - If your pool stains, then there is some metal in there that has to be controlled. I'm sorry, I just don't know where your metals are from, and I don't know where my metals come from either If I ever figure it out I will post - and I hope you do the same We can all help each other by posting what works, because every pool is a little different so there are a lot of things to try

[mbar]

Evan, what would make the water cloud when you put bleach in it? Today when I added bleach, you can see a cloud forming. The water was clear before the bleach. Could it be the sequestering agent? Would it be that there is too much in my water? The ph was low this morning so I added some borax, then I add some chlorine a little while later. My numbers are:
FC - 7
CC - 0
PH - 7.5
Alk - 100
Cal - 170
CYA - 50

I added about 4oz. of metal magic and 2oz. of SeaKlear on Thursday. The water was a little hazy, but when I added the bleach today, it clouded up. My alkalinity has gone up about 20ppms too. We did have a storm last Sunday (that's why I added the sequestering agent and SeaKlear), and it has been very hot here, so I have had a heavier bathing load. I just can't figure it out, maybe you can help

[waterbear]

If you have a lot of seqeusterant in the water I suspect that the bleach was oxidizing some metals and the sequesterant reacted with it to form a metal phosphonate precipitate (remember that Metal Magic is supposed to form 'crystals' that your filter willl filter out). That is about the only thing I can come up with.

[mbar]

I am just stumped Although it may be algae, my pool used up about 7ppms of chlorine today, which is very high with a cya of 50, the only swimmers were my husband and I, I don't think we have that many cooties. I just can't fiure out why it clouds with the addition of bleach, using up sequestering agent sounds right, but I really don't think I have too much sequestering agent in it, I will have to test it with the sequestering kit I just got, and have been too busy to look at