I am struggling to stop our pool going green !?

[flynnboy]

Hi, We have a 17 cu m above ground Intex pool, this is our 3rd season with it. The first season I really did not have much of a problem with it and managed to keep it looking good for the whole season checking chlorine and ph regularly - I use one of those little testers where you compare the colur of your test water against a colured scale on the side of the tubes. However, last year was a different story and I struggled to stop it from going green despite the fact that I did everything I had done in the 1st season.

At the end of the season last year I half emptied it to overwinter and then when I refilled it last Easter I gave it a good shock with THT powdered non stabilised chlorine. I was hoping that being half filled with fresh water and a good shock this might deter the algae....... bit it did not, and I am about going crazy. My tester shows that it has way more than enough chlorine in it and the ph to be 'normal', no-one has even swam in it yet but I am fighting a loosing battle and I am at my wits end as I cannot figure out what is going wrong or how and why algae can still grow when it is full of chlorine and the ph is, according to my tester, normal ? Can anyone please HELP

[Teapot]

You need a decent tester, you are already guessing that emptying might work. You Must, be able to accurately measure CYA and dip strip cannot do that. CYA level controls your pool.

[flynnboy]

You need a decent tester, you are already guessing that emptying might work. You Must, be able to accurately measure CYA and dip strip cannot do that. CYA level controls your pool.

Thanks Teapot, this is the only tester I had on my 1st season and as I said I had no problems ? I have not seen any other testers ?

[flynnboy]

You need a decent tester, you are already guessing that emptying might work. You Must, be able to accurately measure CYA and dip strip cannot do that. CYA level controls your pool.

Hi again Teapot. I have just been reading about CYA and on the face of it that seems like it might be the problem. However, I have looked for a test kit that tests for CYA and I cannot find one ? (I live in France)

Another question, where does CYA come from, i.e. how does it get into the water given that no-one has yet swam in it ? If it comes from the mains water we use to fill the pool then I cannot see what I can do about it because the solutions I have seen say that the only thing you can do is top up the pool with freh water...... I am stumped.

[Teapot]

Ah, were in France, on my way over tonight. You won't find one in France from my travels. I can sort you out a tester if needed.
CYA comes from almost all forms of packaged chlorine, chic, lent, multiaction galets.

[flynnboy]

Ah, were in France, on my way over tonight. You won't find one in France from my travels. I can sort you out a tester if needed.
CYA comes from almost all forms of packaged chlorine, chic, lent, multiaction galets.

I 'think' I know what the problem has been..... 1st season, no problems, used only non stabilised chlorine tablets, 2nd season and this season used 'stabilised' liquid chlorine bought from a mate who has a pool controlled by computer.... not being computer controled I have obviously introduced an uncontrolled amount of stabilised chlorine to my pool which has introduced an excess of CYA ! That is how I see it anyway, has to be !? It would also account for how chlorine levels are still so high after a couple of months exposure to Sunlight.

[ms.carter]

I just recently went through a very similar thing to what you’ve described. I know very little about pool upkeep but despite having a high amount of chlorine, and near perfect ph and everything else, my pool was still green and cloudy. I went through just about every chemical known to man while trying to fix it.

In the end I found shocking it at nightfall and letting the filter run as much as possible helped the most. (I shocked it a total of five times!!!). That got rid of the green tint. I was cleaning off the filter 2-3x daily. Then I used clarifier to get rid of the cloudiness. I did have to treat it with the clarifier multiple times and vacuum the pool afterwards. It took about a month of consistent tlc but now I have a nice clear pool.

As mentioned, I know very little about pool upkeep but if any of this can help you out then I thought it’d be worth sharing. Good luck to you.


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[Teapot]

Ah, were in France, on my way over tonight. You won't find one in France from my travels. I can sort you out a tester if needed.
CYA comes from almost all forms of packaged chlorine, chic, lent, multiaction galets.

I 'think' I know what the problem has been..... 1st season, no problems, used only non stabilised chlorine tablets, 2nd season and this season used 'stabilised' liquid chlorine bought from a mate who has a pool controlled by computer.... not being computer controled I have obviously introduced an uncontrolled amount of stabilised chlorine to my pool which has introduced an excess of CYA ! That is how I see it anyway, has to be !? It would also account for how chlorine levels are still so high after a couple of months exposure to Sunlight.

For a source on unstabilised liquid chlorine, buy 20ltr biddons of eau De Javel from brico sheds around €13 for 20ltrs
Making my way to Loire valley

[flynnboy]

Ah, were in France, on my way over tonight. You won't find one in France from my travels. I can sort you out a tester if needed.
CYA comes from almost all forms of packaged chlorine, chic, lent, multiaction galets.

I 'think' I know what the problem has been..... 1st season, no problems, used only non stabilised chlorine tablets, 2nd season and this season used 'stabilised' liquid chlorine bought from a mate who has a pool controlled by computer.... not being computer controled I have obviously introduced an uncontrolled amount of stabilised chlorine to my pool which has introduced an excess of CYA ! That is how I see it anyway, has to be !? It would also account for how chlorine levels are still so high after a couple of months exposure to Sunlight.

For a source on unstabilised liquid chlorine, buy 20ltr biddons of eau De Javel from brico sheds around €13 for 20ltrs
Making my way to Loire valley

What would I do with eau de javel - are you saying that neutralises CYA ? I have half emptied the pool, today I will refill it and start again with 'unstabilised' Chlorine when needed !

[flynnboy]

We are in Ille et Vilaine not far from Fougeres.

[flynnboy]

For a source on unstabilised liquid chlorine, buy 20ltr biddons of eau De Javel from brico sheds around €13 for 20ltrs

Oh, are you saying that eau de javel is actually chlorine ?

[Teapot]

Yes 9.6% chlorine. Sorry in France I get really bad connection to mobile network.

[flynnboy]

Is 9.6% a 'normal' amount for pool and would I use it just like I would use sodium hypochlorite ? Thanks for your help !

[Teapot]

Yes 9.6 is completely normal, pool shop chlorine would be around 14% if it were fresh enough but you'll pay 2-2.5 times as much. If you call it 10% the maths gets easy 170ml would give you approximately 1ppm. 1.7 ltr would give you a shock level of around 10ppm

[flynnboy]

Thanks a million Teapot ! If you don't mind, how do I work out how much to put in if I want to shock 17 cubic metres ?