From blue to green in 96oz

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Tim23

Tim23

0
LifeTime Supporter
Feb 14, 2010
61
Livingston, Louisiana
Hello all,

Hope everyone is well. Ok I have read everything I could find about metals, and a clear green tint. Here are my numbers as of today.

FC-5
CC-0
TC-5
PH-7.5
TA-110
CYA-50

handunderwater-2.jpg

hand under water


Clearwithgreentint-3.jpg


When we set up/new install and filled with water about a month ago the water was a beautiful blue. We added the amount of bleach we needed per the pool cal. We waited 24 hours and did a test. We needed a little more bleach but so far so good. We noticed the water turned a slight shade of green when we added the bleach. But we figured it was normal because the bleach has a green tint to it anyway and it would go away. We have had no problems with keeping the levels pretty good.

We missed that pretty blue of the liner. So figuring it was metal in the water we went to the local pool store to get some "metal out". We have very soft water here on city water. Iron is not normally a problem here. SO.. I added the metal out per the directions(sprinkling around the edge of the pool). After about 4 hours or so we had the blue back! It looked so good my wife took pictures. LOL We did our test that evening after the sun went down. WOW the FC went down to 1-2. I'm sure that the "metal out" must removed the chorine. I believe the chorine has metal in it right? I added bleach back in to bring the level up and the green came back within an hour. It was funny because when we put the ladder in the pool we could watch each step turn green as we lowered it in.

Anyway sorry it took so long but my question is, are we doing something wrong? Am I missing something?
Thanks for any advice

Tim
 
frustratedpoolmom said:
No, not missing anything - If you simply add more sequesterant, it should help. The dosing instructions are so vague - sometimes you just need more.
Click to expand...

So by adding more sequesterant and then bring the FC level up that it will stabilize to the point we won't have to add anymore sequesterant? The woman at the pool store IS a fan of the BBB method, can you believe that? LOL But she was the one who said its the bleach that is causing the green tint due to the metals in the bleach. My biggest concern was loosing the chlorine. Thanks again for the help

Tim
 
The bleach doesn't have anything in it to cause the green tint. Whats happening is that the chlorine is oxidizing a metal in your water. When metals are dissolved, they are called "reduced". It has to do with the number of electrons in the outer shell of the metal ion. When chlorine is introduced, it "oxidizes" the metal and it drops out of solution. The color you see is the metal that dropped out. Sometimes iron can be a yellowish color. Yellow against your blue liner can look green. Could be a bit of copper, and cant rule out a bit of manganese. Manganese will look somewhat rust color, but again against a blue liner it can have a green tint. You will have to keep a sequesterant in your pool on a regular basis most likely. Use one based on phosphonic acid. You can use an EDTA based chelator. Some on here don't recommend those, but I really don't see an issue with them myself. The phosphonic acid based ones a bit bit better, however.
 
Some metal sequestrants will increase the chlorine demand since the chlorine oxidizes the sequestrant breaking it down. I'm even going through this in my own pool right now because I did an ascorbic acid treatment followed by metal sequestrant (PolyQuat 60 in there too) and after the initial chlorine use associated with getting rid of the leftover ascorbic acid, I now have a much higher chlorine demand. Some of that is due to the PolyQuat 60, but most is due to the metal sequestrant.

Unfortunately, I was unable to find any pool store in the area that carried an HEDP metal sequestrant (HEDP does not break down so quickly from chlorine yet is a powerful metal sequestrant which is why we recommend it). I didn't use one with EDTA, but did use one with "a blend of phosphonic acid and other proprietary metal removers." It was SeaKlear Stain Prevention & Remover (Professional Strength) and I'll never use that again. Though it did make the water slightly cloudy that then dissipated and did help with the metal stains (of course, the ascorbic acid helped a lot as well), I can't stand having the higher chlorine demand that still hasn't dropped. I'm at 3-4 ppm FC per day chlorine usage when I used to be at a little less than 1 ppm FC per day. I added the sequestrant on Saturday so it's only been about 3 days and they usually say it takes about a week for chlorine demand to return closer to normal, but at this rate I'm skeptical.

Have patience as the chlorine will eventually go through all the metal sequestrant. See what it says about the ingredients in the metal sequestrant you are using including looking up the MSDS for the product. If it doesn't say HEDP or 1-Hydroxyethane-1,1-diphosphonic acid (or something very similar), then see about using one of the products listed in the Pool School article on metal stains. Otherwise, every time you add a maintenance dose, you are just adding more to your pool that will use up chlorine.

Richard
 
chem geek said:
Some metal sequestrants will increase the chlorine demand since the chlorine oxidizes the sequestrant breaking it down. I'm even going through this in my own pool right now because I did an ascorbic acid treatment followed by metal sequestrant (PolyQuat 60 in there too) and after the initial chlorine use associated with getting rid of the leftover ascorbic acid, I now have a much higher chlorine demand. Some of that is due to the PolyQuat 60, but most is due to the metal sequestrant.

Unfortunately, I was unable to find any pool store in the area that carried an HEDP metal sequestrant (HEDP does not break down so quickly from chlorine yet is a powerful metal sequestrant which is why we recommend it). I didn't use one with EDTA, but did use one with "a blend of phosphonic acid and other proprietary metal removers." It was SeaKlear Stain Prevention & Remover (Professional Strength) and I'll never use that again. Though it did make the water slightly cloudy that then dissipated and did help with the metal stains (of course, the ascorbic acid helped a lot as well), I can't stand having the higher chlorine demand that still hasn't dropped. I'm at 3-4 ppm FC per day chlorine usage when I used to be at a little less than 1 ppm FC per day. I added the sequestrant on Saturday so it's only been about 3 days and they usually say it takes about a week for chlorine demand to return closer to normal, but at this rate I'm skeptical.

Have patience as the chlorine will eventually go through all the metal sequestrant. See what it says about the ingredients in the metal sequestrant you are using including looking up the MSDS for the product. If it doesn't say HEDP or 1-Hydroxyethane-1,1-diphosphonic acid (or something very similar), then see about using one of the products listed in the Pool School article on metal stains. Otherwise, every time you add a maintenance dose, you are just adding more to your pool that will use up chlorine.

Richard
Click to expand...

I emailed AquaChem (the stuff sold at Walmart) and they sent me a MSDS sheet for their sequestrant. I forwarded it to JasonLion. Believe it or not, the stuff is the HEDP variety. It has phosphonic acid in it. I wonder if it's cheaper because maybe it just has less of the acid in it? I bought 2qt over the weekend and have yet to compare it's dosage rate with Proteam or Magic Jacks. It may wind up costing the same by the time I account for dosage...still at least I can get it local without having to add shipping to the cost.
 
Again thanks for all the info, it is all so very helpful! I just have to share this with you all. First of all I mean no disrespect to anyone if this comes across that way. I was at the local pool store this afternoon picking up another bottle of "metal out". The young man working there was trying to find out why I was buying more and started asking a bunch of question. I avoided telling him I was using bleach because I didn't want to have to answer all the questions if you know what I mean. Well I finally told him I was using bleach for my chlorine.

It was like the invasion of the body snatchers. His expression changed and had this confused look and said "you can't do that". I said "why" (playing dumb), he said "bleach is unstable, it would cause a spike in your FC level and then not last". Of course his next statement was.."thats why you are having all your problems"! LOL Anyway after getting a lesson on how bleach will cause problems and that I need to use "easy pool" or "Eclipse" I got what I wanted and thanked him for the info. On the way out I needed some more reagents/refill for my test kit. He said that they don't carry them because the industry is getting away from drops and they are all going to strips. So within the next week I will be ordering my TF-100. All in all I know he thought he was trying to help.

I just thought it I would share this with you. Again thank you all for the help!

Tim
 

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PaulR said:
Seems to me I've heard that after putting in the sequestrant, you should raise FC slowly... or am I thinking of something else?
--paulr
Click to expand...
That's true. The definition of slowly depends on the situation though. I'm adding 2 qts at a time which is a little over 1ppm for me and still getting the green cloud. Heck, maybe I need to do a cup at a time every 4 hrs and see what happens.
 
Also, the reason for adding chlorine slowly is two fold. First, for hypochorite sources of chlorine, you don't want to shock the pool too soon as that increases the pH and can lead to precipitation of metal stains again. Second, a higher FC level (technically, FC/CYA ratio) will break down the metal sequestrant more quickly.

I don't think there is any real problem with the higher FC itself in terms of oxidizing ferrous iron (Fe2+) to ferric iron (Fe3+) since that should happen relatively quickly with even low FC levels which is why you want to use ascorbic acid followed by metal sequestrant BEFORE adding any chlorine at all so that you tie up the ferrous iron before any chlorine can oxidize it to ferric ion (which is what stains). So I figure the main issues are the higher pH side effect and the faster oxidizing of the metal sequestrant.

I've got my FC up a bit now to accelerate getting rid of the sequestrant, but the pH is at 7.5 (I've got around 60 ppm Borates in the water, so that helps keep the pH stable even at higher FC levels from chlorinating liquid). I haven't had the sequestrant before and didn't have a problem with this kind of stain until the pH got higher so I'm just going to manage the pH going forward.
 
chem geek said:
Also, the reason for adding chlorine slowly is two fold. First, for hypochorite sources of chlorine, you don't want to shock the pool too soon as that increases the pH and can lead to precipitation of metal stains again. Second, a higher FC level (technically, FC/CYA ratio) will break down the metal sequestrant more quickly.

I don't think there is any real problem with the higher FC itself in terms of oxidizing ferrous iron (Fe2+) to ferric iron (Fe3+) since that should happen relatively quickly with even low FC levels which is why you want to use ascorbic acid followed by metal sequestrant BEFORE adding any chlorine at all so that you tie up the ferrous iron before any chlorine can oxidize it to ferric ion (which is what stains). So I figure the main issues are the higher pH side effect and the faster oxidizing of the metal sequestrant.

I've got my FC up a bit now to accelerate getting rid of the sequestrant, but the pH is at 7.5 (I've got around 60 ppm Borates in the water, so that helps keep the pH stable even at higher FC levels from chlorinating liquid). I haven't had the sequestrant before and didn't have a problem with this kind of stain until the pH got higher so I'm just going to manage the pH going forward.
Click to expand...


Last year when I ran into this I asked what slowly meant. The answer was that you could jump to your min FC number in one step. For me, this is about a 182oz jug of 6%. When this caused trouble I backed up to the 2qt, still more trouble. What would you define as slow?


I checked my numbers at lunch and the chlorine is finally holding:

FC 3.5
CC 0.0
pH 7.2
TA 70
CYA - I haven't measured it, but it should be around70. It was 20 when I measured and have since added 10#. I'll probably do that test this weekend.

I've barely been able to hold FC at 1.5. I ramped up the pump time and swg % and have been adding bleach which has been generating the clouds. Glad all of that seems to be behind me. The pool needs a good vaccuum but otherwise looks good. Nighttime temps have dropped it back to 77 degrees.
 
There are two aspects to "slowly" here. One is to limit the amount of water subject to higher than target levels of FC. Adding chlorine more slowly means more water involved in the mixing process and less total water subject to high FC levels during the mixing. The other is to give the sequestrant time to bind to the metals in the water.
 
JasonLion said:
There are two aspects to "slowly" here. One is to limit the amount of water subject to higher than target levels of FC. Adding chlorine more slowly means more water involved in the mixing process and less total water subject to high FC levels during the mixing. The other is to give the sequestrant time to bind to the metals in the water.
Click to expand...

Ahhh, so what I should have done regardless of quantity, was dump small amounts at various places instead of the whole quantity in front of one particlar jet. Maybe each corner and mid length on the long side so that you have 6 discharge points. That does make sense.
 
Ok we added the sequestrant yesterday morning. We didn't check the FC last night because we figured it would be low and we wanted the sequestrant to work for a while. Checked the FC this morning and it was at 1. So we added a small amount of chlorine in different places around the pool. I will check it this evening. Maybe this way it won't have that big jump and kill the sequestrant working. We will try and bring the FC level up slowly. Hope this is right.

Tim
 

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