green tint in algae free (pretty sure) pool help

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outpost

Well-known member
Jun 1, 2020
53
Long Island
New 18' round intex pool. Filled with municipal water 1 week ago. Have maintained chlorine above 2ppm since water went in. Has been the same "crystal clear but has a green tint to it" color since the water went in. Sand filter running pretty often I would say average between 18 and 24 hours a day. No slimey feeling on pool walls or anything.

I am pretty confident it is not algae as I have maintained chlorine religiously since the water went in and it went in the pool this same color. I do not have access to an iron or copper test. Many fellow pool owners who live near me and have seen it have said they think it is iron or copper in the water including a friend who is a licensed commercial pool operator. He suggested I add a Metal Out type product (The one I have available to me would be a different brand but it is essentially a phosphoric acid derived mineral/copper binder)

I have read pool school and plan on using your methods with my pool so I am wary of dumping anything in the pool other than the essentials. What do you guys all think?

My current readings:

TC: 2.8
FC: 2.8
ph: 7.4
TA: 60
CH: 50
CYA: Below 30 - (My plan is to chlorinate with stabalized chlorine which I am currently doing until my CYA gets to about 30-40 then switch to stabalizer free liquid chlorine)

Any advice appreciated before I go ahead and dump in this metal binder.

Thanks!

(Pic for reference)

small_Green.jpg
 
Last edited:
If you would, put your pool information in your signature. Settings/signature

What test kit do have? Put that in signature too.
This will help the experts guide you.
I wouldn’t put the metal binder in until they take a look.
 
Do you have a skimmer? If so, put some paper towels in it and see if they turn brown ---
 
Ill check them first thing in the AM .. so far they are looking the same shade of white as when they went in.

Another question - what could some of the downsides be if I did put a phosphoric acid derived metal binder in? (Other then wasted money)
 
Thanks .. I am much less suspicious of iron as I am copper. Paper towels so far are still white. Copper will turn the paper towels brown also? Water for pool was filled from house with all old copper lines, a copper feed to the main, and old mains that also I believe still have large copper sections still within the 150 miles or so of mains my water district maintains. I am sure there is some copper in the water I just don't know how much.
 
Copper is unusual in potable water systems. It is EPA controlled so it should be reported by the water utility.

Copper will not turn the paper towels brown.
 

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With fresh water it would be unusual to need to SLAM. If you are confident there is copper in the water (check your water utility reports) use the metal sequestrant. The sequestrant must be added on a regular maintenance basis.
 
There is copper in their water report but its hard to know how much it really is, and at what point in the distribution system they are measuring ..

.22mg/l is the amount in the report. Perhaps when there is 7000 gallons that really small sounding amount is not so small ...

Also interestingly enough, the water report from last year shows a violation amount of iron .. between 300 and 2700 mg/l. (I believe 300 is the regulatory limit)... I will check the paper towels again in the morning before I do anything else.

Thanks so much!
 
.22 is significant copper. Our point of concern for staining is 0.3. No way to get copper out of the water either.
 
Update

I'm glad to know .22 is significant copper and likely the reason for the color. I will tell you what has transpired this morning and I guess we can all try to figure this out but here we go .. pool clear and same shade of green this morning. Paper towels were still as white as when I put them in. Picture below. I took a deep breath and dumped the quart of the "liquid magnet" in the pool. It says specifically it will bind with copper. It has been about 2 hours and the green is at least 50% better .. I wouldn't say it is 100% gone entirely but it has shifted significantly. Picture attached.

So was it the "significant" copper? Adding the binder was the only thing that changed in the last week. I would assume yes but you said there is no way to remove the copper .. should I expect the green tint to return? Should I be adding a small amount of this stuff now every week? I am very happy, yet also I think maybe just as confused.

Thanks for all your help so far.

papertowel.jpg
blue.jpg
 
Yes - It has that information. I am just trying to keep as close to the "program" as possible and only want to add the fewest things as possible to the pool over the long haul. I will add the maintenance dose to my regimen.

You had said on the one hand add the maintenance sequestrant dose, but on the other said there is no way to get the copper out of the water, so I'm just trying to get it all square in my head whats going on and what I am doing. I am one of those likes-to-know-the-exact-reason-I'm-doing-something and why kind of person which is why I find this site so wonderful. If the copper never actually leaves the pool - what is the sequestrant doing .. why do you think the pool color appears to have shifted for the better and what should I expect the maintenance sequestrant to be doing for me for the long haul?

Sorry I have so many questions! I just don't want to close the book on this without fully understanding whats happening and what I am doing going forward.
 
A metal sequestrant holds onto metals to prevent them from staining pool surfaces. It's only needed if you've got metals (iron, copper, manganese) in your water, such as sometimes occurs in well water.May 25, 2011
 
Msch99 said:
A metal sequestrant holds onto metals to prevent them from staining pool surfaces. It's only needed if you've got metals (iron, copper, manganese) in your water, such as sometimes occurs in well water.May 25, 2011
Click to expand...

Thanks - I got that part. What I guess I am trying to resolve is this - the sequestrant bottle says "Works by binding heavy metals which are formed into a complex. They can then be removed by filtration". Mknauss says the cooper can never be removed from the water. Conflict there - since I trust you guys as experts I am going to assume mknauss is correct and the bottle description is fibbing. Also, the sequestrant definition you quoted talks about long term staining prevention - it doesn't say anything about every day water color management which is what started all this. What I don't yet fully understand is how is the sequestrant helping my water color, and if the copper is not actually ever leaving the pool, is it just "holding on" to the copper and that is what is helping the color but over time it will "let go" of the copper and I will have to keep adding the maintenance amount to keep that from happening?
 

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