From blue to green in 96oz

[JasonLion]

Clouding after adding sequestrant is fairly common. It usually comes from calcium binding to sequestrant and clumping to form an extremely fine dust. The clumping either breaks up after a couple of days or makes particles large enough to be filtered out.

 

[chem geek]

This wasn't Jack's since no one had that in my area and I didn't want to wait for shipping, so I got "SeaKlear Stain Prevention & Remover (Professional Strength)" which has "a blend of phosphonic acid and other proprietary metal removers." It may not be just HEDP like Jack's and they say on the bottle that cloudiness can occur and will dissipate over time which is exactly what happened. I'll never use this product again, that's for sure. It's not the cloudiness, but the much higher chlorine demand that's a pain. I would assume that using HEDP the change in chlorine demand might be much smaller, maybe not even noticeable, though that's not from experience.

As for zinc paint, chlorine normally oxidizes zinc so I'm not so sure how well that would work. On the other hand, the other mounts that were further away from the Trichlor pucks don't show any rusting so whatever they've got has lasted for years and been OK. I'm just guessing that it's galvanized steel -- I don't really know. When I get back from my trip I'll take some pictures of it to post (probably start another thread on this issue).

 

[bk406]

Whenever I've used Jack's, i have not seen an increase in chlorine demand at all. I'm hoping that the HTH metal control i bought will work in a similar way. The active ingredient on the bottle is the same as Jack's, but the formulation could be different.

Jason, interesting on the cause of clouding, makes sense. Maybe I've never seen it since I keep my calcium pretty low because I have a vinyl pool.

 

[Tim23]

Hello again,

I need some clarification here,(pardon the pun). I'm still confused about the metal problem I seem to have. I understand that the chlorine is reacting with the metals in the water. If I am right in saying this... the chlorine reacts with the metal and turns it green, kind of like a test strip does when introduced to the pool water right? The chemicals that are put on the strip cause the color change to indicate what the ppm or level of the chemicals that are in the pool water, is this correct? I'm trying to put this in laymen's terms to "KISS"(keep it simple stupid). Oh btw I am using a 6 way test kit not the strips even though I have them. I will be ordering my new kit soon but I want to use up what I have for now.

SO... where I am getting lost is here....My FC is between 3-5 when tested in the am, and the water has its normal green tint. I haven't added any bleach within the past 24 hours. I used "HTH metal control" this time to see if I would get a different result and also it is easy to get and cost $11 vs $17 from the pool store they sell "Regal" brand. Not sure if they have the same compounds or not. The pool store brand is call "metal out". I'm thinking just a different wording. The HTH brand active ingredient is "Hydroxyethylidene Diphosphonic Acid" (however you say that).

Ok back to "KISS"! So 2 or 3 hours later I have beautiful blue water or should I say a beautiful blue liner. LOL The water is crystal clear. I do a test to see what my FC is and it is at 1. This is where I get frustrated/confused. What it seems to me that is going on here is the "Metal Control" is just removing what is causing the water to turn green in the first place,the chlorine reacting with the metals! I know you have to have chlorine but I don't want the metals. Living in the south I worry that I will get algae very easy due to the amount of rain we get and the warm temps. I would feel more comfortable with a FC around 3 just to be safe if needed. Am I wrong here? Will a FC level of 1 be ok as long as all other levels are ok?

I waited 36 hours and kept a close eye on the FC level which was at 1 or less. So as a test I added a quart of bleach. With in 30 min it was back to its mean green self, which is wild to watch 19k gallons go from blue to green from only 32 oz! Normally to maintain my FC level I use the "Pool Cal" to double check how much to add even though I think I have a handle on how much to add compared to levels from test. This time I added less just to see if it would bring up my FC a little and if the water would turn green again. Of course it did. FC level didn't change much, maybe a solid 1.

Sorry so long just to get to these questions but I just wanted to explain what actually is taking place with a time line. Like I said I believe I do understand what is happening, but what I see is by adding the metal remover (so its called) isn't removing any metal. Its stopping the reaction by removing/reducing the chlorine right?

1. Is there a permeant solution for this? I understand when new water is added more metals will be added. I try not to let the water level get to low so less water will be added.

2. Could anything else in the water/levels cause this same type of reaction? Isn't alkaline a metal? If so, would a high alkalinity level cause the same problem? I noticed when I add the sequestrant (i.e. metal out) my ph drops and as pool school points out (yes I read it, LOL ) lowering the ph lowers the alkalinity. My PH has been a little high along with my alkalinity. I also noticed when I add the bleach the PH goes up. My PH hovers around 7.5 but sometimes closer to 7.8 with my alkalinity around 110. It used to be much higher but I added the required amount of Muriatic (hope I spelled that right) acid but no change to the color of the water.

3. Can having 0 CH have any effect on the metals or reaction on the metals that may cause some of my problems? We never added any calcium chloride (even though the pool cal said it was required) because I didn't think it had that big of an effect on a vinyl pool. But what do I know! :?

4. Could there be something with the liner or filter etc... that is causing this same reaction? New pool installed about 2 months ago. Only reason I ask is because we had an 24' Intex temporary pool in the same place as our new pool but never had a green tint problem except when the wife forgot to add chlorine and we had a algae break out. She would just add a bunch of Shock and Swim (we were clueless back then) but still no green tint/metal problems. Now I do all the balancing :lol: , Thank you TFP!!!!! I now enjoy taking care of our pool! Now if I could solve this problem all would be right. I guess what's bugging me the most is, I have to be missing something! I would have thought with the large amounts of chlorine my wife used to throw in our old pool that we would have experienced the same problem. Is there anything in standard store bought chlorine etc.. that might have something in it that I may be missing using the BBB method? According to the pool cal and testing we really only require the bleach out of the BBB method unless I'm missing something.

This site has helped us so much. We have come such a long way in a very short time. If you would have asked me a few months ago what my FC or PH, or CYA etc was I would have been lost! What I have learned from TFP can be summed in these words.......


"LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!


Thanks again for the help,
Tim

I may not be an expert when it comes to a pool, but I have been an appliance tech for over 27 years so if you have a question feel free to ask/PM me.

 

[Tim23]

Clouding after adding sequestrant is fairly common. It usually comes from calcium binding to sequestrant and clumping to form an extremely fine dust. The clumping either breaks up after a couple of days or makes particles large enough to be filtered out.

I wrote,

3. Can having 0 CH have any effect on the metals or reaction on the metals that may cause some of my problems? We never added any calcium chloride (even though the pool cal said it was required) because I didn't think it had that big of an effect on a vinyl pool. But what do I know!

Seems like I'm about to answer my own question with help from a quote from Jason.

If I am right here, and using what Jason pointed out about the clouding/clumping.......... If no calcium in present in the water(which I have 0) there is nothing for the sequestrant to attach to. This would be why the metals are never filtered out!

Does this make since????

If this is right I feel so stupid!

Tim

 

[chem geek]

It's actually the opposite. If there is no calcium to bind with the sequestrant, then metals would theoretically bind more quickly and in larger quantity to the metal sequstrant. Basically, calcium and metals compete for binding to the sequestrant, though a good sequestrant is designed to bind to iron and copper much more than to calcium. So when you add metal sequestrant, some calcium binds to some amount of it, and that causes some cloudiness, but any metals in the water will preferentially bind to the sequestrant much more than calcium will. Furthermore, any of the calcium bound to sequestrant that then gets caught in the filter will be able to scavenge any additional metal added to the pool as the metal is more likely to bind to the sequestrant than the calcium so will kick the calcium out and replace it with the metal instead (even in the filter).

As for the chlorine demand, that is most likely chlorine oxidizing some of the metal sequestrant itself and that is not really a good thing. That's why the better metal sequestrants, based on HEDP, don't exhibit this or at least not as much. Depending on the specific metal sequestrant, the chlorine may not be fully oxidizing the sequestrant at first, but is instead binding to a nitrogen site in the sequestrant, very much as with Combined Chlorine (CC). Again, HEDP doesn't do this because it doesn't contain any nitrogen sites.

So, in short, the cloudiness that initially results and then disappears is not a problem at all. The chlorine demand is more of a question and does not occur with all metal sequestrants.

 

[Tim23]

It's actually the opposite. If there is no calcium to bind with the sequestrant, then metals would theoretically bind more quickly and in larger quantity to the metal sequstrant. Basically, calcium and metals compete for binding to the sequestrant, though a good sequestrant is designed to bind to iron and copper much more than to calcium. So when you add metal sequestrant, some calcium binds to some amount of it, and that causes some cloudiness, but any metals in the water will preferentially bind to the sequestrant much more than calcium will. Furthermore, any of the calcium bound to sequestrant that then gets caught in the filter will be able to scavenge any additional metal added to the pool as the metal is more likely to bind to the sequestrant than the calcium so will kick the calcium out and replace it with the metal instead (even in the filter).

As for the chlorine demand, that is most likely chlorine oxidizing some of the metal sequestrant itself and that is not really a good thing. That's why the better metal sequestrants, based on HEDP, don't exhibit this or at least not as much. Depending on the specific metal sequestrant, the chlorine may not be fully oxidizing the sequestrant at first, but is instead binding to a nitrogen site in the sequestrant, very much as with Combined Chlorine (CC). Again, HEDP doesn't do this because it doesn't contain any nitrogen sites.

So, in short, the cloudiness that initially results and then disappears is not a problem at all. The chlorine demand is more of a question and does not occur with all metal sequestrants.

Thank you so much for the info!!! Let me back up here a bit... I will try and keep this short :lol:. New pool set up, tested our tap water (but not for metals) and used the results we found to enter in the pool cal. Added the recommended amount of bleach to get a base line, the water turned green almost right away. Waited a day or so and added CYA, then tested again. The waited a few days and then added the proper amount of M. acid. Everything was in range and water was clear and green.

I didn't add any Cal Chloride at this point because like I said I didn't really think it was as important at this point. I added the first bottle (from pool store) or "metal out". Water turned a nice blue but chlorine was down to 0.5. So I added bleach, then green again. Let that go for a few weeks keeping chlorine up to 3 to 5.

Tried another bottle of "metal out" but this time let it stay in for 36 hours. Water turned blue, FC down to 0.5. I was afraid to leave it any longer so I added bleach and the green came right back with in minutes. At this point I must be doing something wrong. So I started this thread. Then I decided to try the HTH brand. It seemed to work much better, but it ate up the chlorine much faster. I went from FC of 3 to .5 in a little over an hour. So I had to add bleach back to bring the FC back up. Of course green in about 25 min and my FC back to 3.

Yesterday evening checked my numbers and FC is 3, so I tried another bottle of the HTH again this morning thinking maybe I didn't leave it in long enough for it to work, even if the water turned blue. I put it in around 7 am this morning and by noon today it was blue. I checked the FC and it was down almost to 0 to .5 . So that is what prompted me to add the post earlier.

I thought I had it figured out when I saw Jason's post about cal chloride binding with the sequestrant. I had bought a 50 lbs of the chloride back when I set the pool up so I had it to put in. If I remember right PC said put in 50 lbs. I added it about an hour ago. Water is perfectly clear and sparkling blue but with a FC-.5 as of 15 min ago. We are expecting heavy rain tomorrow so I am afraid to leave the chlorine that low with all the extra water we may get, but I don't want to see the green again!

So after reading what chem geek said I'm afraid I will be right back to square 1 if I add the bleach back. Sounds like I may need a different sequestrant. Chem Geek, thanks for the help!

Question, Pool Cal says for me to add 96oz of bleach to bring my FC back within range..... If I added it a little bit at a time (i.e. 10oz now, 10oz in about 2 hours 10oz in the morning and so on until the 96oz is added) could this help or would the ppm still be the same either way so by the time I get it all in then it will be green? Any chance that the Calcium Chloride will help even if the sequestrant I'm using doesn't seem to do the trick alone?

Tim

 

[chem geek]

If the water is green, then it's more likely to be copper rather than iron in which case the chlorine itself isn't the cause of it turning green, but rather the increase in pH from when you add chlorine (if the TA is high, then it could be iron carbonate which is greenish). This is why it is said to very slowly add chlorine and raise its level after you've added a metal sequestrant and to not go to shock levels for at least a week. If you want to prevent the green from showing up, you can lower the pH first (shouldn't be necessary to go lower than 7.2) before adding the chlorine. Why don't you try that and see how that goes. See if the lower pH helps to prevent the water from turning green.

Eventually, you'll want to get the pH more to normal range, but hopefully by then the metal will all be sequestered. The only way to completely remove the metal will be with water replacement or perhaps with some filter cleaning if the type of sequestrant you are using precipitates into the filter.

Note that if the metal you have in the pool water is iron, then an ascorbic acid treatment is needed for the metal sequestrant to work since it won't bind with ferric ion and will only bind to ferrous ion. Chlorine oxidizes ferrous to ferric while ascorbic acid reduces ferric to ferrous. Some metal sequestrant products contain a reducing agent in the product itself which is usually why they recommend having a low chlorine level (usually <= 1 ppm FC) before adding such product.

 

[bk406]

If the water is green, then it's more likely to be copper rather than iron

I'm not so sure thats true, in some cases. I know for a fact my metal issue is iron. But, my pool water is nice and green when I have the issue. It's because the redish/yellow color of the iron looks green against the blue liner. Of course, testing the metal type would be helpful.

 

[chem geek]

Ah yes, yellow-red against blue can look green. I often forget about that. Thanks for reminding me.

 

[frustratedpoolmom]

Note that if the metal you have in the pool water is iron, then an ascorbic acid treatment is needed for the metal sequestrant to work since it won't bind with ferric ion and will only bind to ferrous ion. Chlorine oxidizes ferrous to ferric while ascorbic acid reduces ferric to ferrous. Some metal sequestrant products contain a reducing agent in the product itself which is usually why they recommend having a low chlorine level (usually <= 1 ppm FC) before adding such product.

Richard, can you elaborate on this - are you saying even if there is no staining, when iron is present they should still follow AA treatment instructions and use sequesterant to get the sequesterant to work better? I'm confused...

 

[chem geek]

[EDIT] I'm probably wrong about the following, at least with regards to HEDP. See my additional post here later in this thread. [END-EDIT]

Yes, even if there is no staining, if you want to remove iron from the pool you need a reducing agent in the water to convert the iron into a form that can be bound to the metal sequestrant. This may not require an ascorbic acid treatment since many metal sequestrants already have reducing agents in them. Usually, if the metal sequestrant says to lower the chlorine level first to <= 1 ppm FC, then it probably has a reducing agent in it already. If one is unsure or if they know they are using a metal sequestrant that doesn't have a reducing agent, then they can separately do ascorbic acid first.

Basically, if there is iron in the pool, any chlorine will oxidize it to the ferric ion state that won't get bound to metal sequestrants. So a reducing agent (from somewhere) must reduce ferric ion to ferrous ion first for the metal sequestrant to bind to it.

 

[reindeerboy]

I have found that the Metal Master product from ROBARB is great. Ordered it online from poolgeek.com and its much cheaper than purchasing it at the pool store as they sell the same darn stuff for $6.00 more per bottle. Yea thats right, 6 bucks more a bottle. I buy mine by the cases so its even cheaper and I also order my polyquat Algae 60 from them. Dont need to use much as I usually only use it upon winter closing and spring opening, but ordering a case at a time sure has saved me some cash!

Thought I would share.

Thanks

 

[bk406]

I'm still a little confused too. I was under the impression if you could see the metal color in the water, it was oxidized, and if it was dissolved (reduced) you can't see it. Reason I ask is because when I add Jacks or HTH, it clears it up. If the iron is oxidized, then it shouldn't clear it?
Unless:

1) My assumption is untrue that the color i see is due to reduced iron,

2) or the phosponic acid based sequesterant has a reducing agent in it

3) a combination of both of the above.

I will say I've never noticed a FC demand increase when I add sequesterant of the above type

 

[chem geek]

It's probably either #2 above or I was wrong, but the amount of reducing agent can be fairly low such that it would only consume perhaps 1 ppm FC of chlorine beyond the initial 1 ppm FC that may be there when you add it. The amount of metal concentration in the water isn't going to be much above 1 ppm since it will precipitate out if higher (depending on the pH).

I also see that some phosphonate metal sequestrants, such as HEDP, can also bind to ferric ion as well, though not as strongly (see here for ferrous ion and here for ferric ion).

So when using HEDP, at least, it seems you don't need to worry about reducing the iron as it will be able to complex with it in its oxidized state, at least somewhat. That's good news and yet another reason to use HEDP over some other type of metal sequestrant.

So I was wrong to be so general about needing a reducing agent. It helps with some other metal sequestrants, but is probably not needed for HEDP.

 

[bk406]

Thanks Richard.

The amount of metal concentration in the water isn't going to be much above 1 ppm since it will precipitate out if higher (depending on the pH).

.

This actually makes sense to me as well. When I've had the best luck getting iron to precipitae out is when the concentration was above 1 ppm and the pH is at 7.8+. When I tried it this season, my pH was at 7.2 and the iron was at </=0.5 ppm. I didnt get much to come out, but a quart of HTH cleared it up within 4-5 hours. I did notice a slight tinge coming back a week later, but I added 1.5 cups of HTH metal control and it cleared again. I suspect I'll need to add a cup or so every 7-8 days. As I've found, it doesnt take much metal to color the water a bit, unfortunately.

 

[Tim23]

Update,

I know this sounds bad but..... I'm not sure what I did, but this morning I woke up to a blue pool!!!!

I think I used advice from everyone and not sure what really worked. I hope I'm not speaking to soon. Here is what I did yesterday in order.

1. As I posted earlier I added the sequestrant " HTH metal control" in the AM (around 7am). By 12pm the pool was back blue. FC was at 3 before sequestrant and around .5 after. As Richard (chem geek) stated maybe I should have waited till the FC was around 1. Instruction didn't state to do that on this brand that I recall.

2. After posting here and reading and getting some great advice and info I, vacuumed up some sand that had been sitting on the bottom since we installed the pool (got on the liner durning installation) along with those pesky seeds that fell from a nearby tree. Water has been a little to cool to swim yet, go figure living in Louisiana. This time last year we were swimming in our old pool by late March early April. Water temp 76* now.

3. Added/bushed in 50# of calcium chloride around 4pm and ran pump on hi. As I stated I had it when we did our fill but had never put it in. I wanted to cure the green problem first, so I thought.

4. At 10:30pm, I added 20oz (it needed 96oz per pool cal) of bleach to raise the chlorine some due to some heavy rain we were to have today. I was worried that my FC level was already low.

5. At 6am this morning (woke up by heavy rain) and the water was still blue. So I added 50oz of bleach. That brings me to a total of 70oz of the 96oz required.

6. At 10am this morning, pool still blue!!! Turned pump to low. By now the water would have normally tuned green again, heck after the first 32oz it would have been green.

SO..... What did I do right???? I still need to add the other 26oz of bleach but I thought I should run a test this morning before doing so, here are my results.

FC-2
CC-0
CH-280
TA-100
PH-7.5
CYA-40

Not to bad right? Do I wait to add the rest of the bleach? Even though I am below my target FC range would you think its ok for now?

Water is very clear but we are overcast here and have had rain showers on and off. I guess it could have been a combination of all the things I did.

I'm not a 100% convinced the problem is solved yet, but look at the knowledge I have gained so far! Knowledge is priceless, and so are the folks here! Thank you.

Tim

Gonna post some pics in just a bit!

 

[Tim23]

Here are a few pics of what I have been dealing with until today! I'm sure this has been seen before. So far so blue!


This is of course is the green.



This is a few hours later after adding the sequesterant.



Waited 36 hours, tested and it needed chlorine. Added the bleach and, Green again.





This is what it looked like this morning. It was nice to see that blue rather then a green. When the grass grows back I will enjoy that type of green! Everything is still a little messy around the pool.




This is today after all the help. Was able to add some bleach and it seems to have held its color this time. It's overcast today so it doesn't show the POP in the picture but it looks great. FC is still at 2.







Thanks again.

Tim