Hi from a green pool in central France!

[Wendypoolboss]

In third year of owning an above ground 8x4 pool with a sand filter in our second home. Thought I knew what I was doing until suddenly I can’t clear a bright green soupy pool!

 

[drsipe]

It appears that you have algae.

I see that you are in France, are you able to get either the TF-100 or Taylor K-2006 test kit?
With one of these kits, you can run accurate testing to evaluate the water chemistry.
How do you sanitize your pool in France?

Please create a signature, this will provide us with information that will allow us to help you.

Create Your Signature - Further Reading

www.troublefreepool.com

Algae forms when the chlorine levels in your pool are too low, the bad news is that it takes much more work and chlorine to kill an algae bloom than it takes to prevent one. The good news is that you have found TFP and we can help you.
Here is a link to pool school's section on algae:

Algae Archives

www.troublefreepool.com

Here is a link to begin your education on maintaining a sparkly clear water:

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

 

[Wendypoolboss]

It appears that you have algae.

I see that you are in France, are you able to get either the TF-100 or Taylor K-2006 test kit?
With one of these kits, you can run accurate testing to evaluate the water chemistry.
How do you sanitize your pool in France?

Please create a signature, this will provide us with information that will allow us to help you.

Create Your Signature - Further Reading

www.troublefreepool.com

Algae forms when the chlorine levels in your pool are too low, the bad news is that it takes much more work and chlorine to kill an algae bloom than it takes to prevent one. The good news is that you have found TFP and we can help you.
Here is a link to pool school's section on algae:

Algae Archives

www.troublefreepool.com

Here is a link to begin your education on maintaining a sparkly clear water:

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

Thanks I’ll get reading! We go between France and UK, so cover pool when not here and winterise in November. I am searching for thé recommended test kits, don’t think they’re available here in France or UK. Will keep trying. I have 7 in 1 strips atm. We sanitise with chlorine multi-function tablets and chlorine shock tablets when required. Have struggled to balance ph and alkalinity levels lately and lost faith in the more simple test strips hence bought the 7 in 1!

 

[Mdragger88]

The tablets most likely are trichlor - for every 2 ppm of fc (free chlorine) you get from them you also add 1ppm of cya. Dichlor is even worse- it’s a 1:1 increase.
The fc gets used up daily but the cya remains until you exchange water & builds to an unmanageable level.
This makes it harder & harder to maintain the necessary fc level required for daily sanitation & things go south.


If your cya is quite high it’s best to exchange water to lower the cya level before attempting the SLAM Process as it’s impractical to attempt to maintain such high fc levels.


Here’s some information on obtaining adequate test kits outside the US- some have had luck on amazon.

Pool Test Kits - Further Reading

www.troublefreepool.com

Dichlor & Trichlor are also quite acidic so they lower ph & can crash ta in short order. We recommend liquid chlorine for this reason.
Until you get drop based kit to get more accurate data you can add 5ppm worth of liquid chlorine/unadulterated bleach (no splashless/cloromax/fabric conditioners) each day to keep things from getting worse. Pour it slowly infront of a running return & brush the area.
Use PoolMath to calculate amounts.

 

[Wendypoolboss]

The tablets most likely are trichlor - for every 2 ppm of fc (free chlorine) you get from them you also add 1ppm of cya. Dichlor is even worse- it’s a 1:1 increase.
The fc gets used up daily but the cya remains until you exchange water & builds to an unmanageable level.
This makes it harder & harder to maintain the necessary fc level required for daily sanitation & things go south.
View attachment 521186

If your cya is quite high it’s best to exchange water to lower the cya level before attempting the SLAM Process as it’s impractical to attempt to maintain such high fc levels.
View attachment 521187

Here’s some information on obtaining adequate test kits outside the US- some have had luck on amazon.

Pool Test Kits - Further Reading

www.troublefreepool.com

Dichlor & Trichlor are also quite acidic so they lower ph & can crash ta in short order. We recommend liquid chlorine for this reason.
Until you get drop based kit to get more accurate data you can add 5ppm worth of liquid chlorine/unadulterated bleach (no splashless/cloromax/fabric conditioners) each day to keep things from getting worse. Pour it slowly infront of a running return & brush the area.
Use PoolMath to calculate amounts.

Thank you for this detailed information. My brand new 7 in 1 strips (all I have at the moment) are showing the CYA as quite low (about 20-30ppm) and the free chlorine as 3 ppm (though my liquid test kit (simple version) is showing way higher in mg/l.) Total chlorine was at 9 ppm on the strip. Ph is 7.8 ish on strip and 7.7 on liquid test.
All this, after the pool store tested and went straight for a ‘very high’ Cya and high chlorine, telling me the only option was to empty the pool and refill. Pretty sure that won’t be allowed here anyway at the moment with water restrictions. I think I now know why you don’t rate store tests!!

 

[drsipe]

With the testing methods at your disposal, unfortunately test strips are extremely inaccurate, unless you can get a test kit we won't know exactly what you need to correct your water chemistry.

We also don't believe pool store testing, but I believe that they are on the right trail, your CYA is probably high due to the use of chlorine tablets, which increase the CYA along with the chlorine. The tablets dissolve and put chlorine and CYA in the pool, the chlorine breaks down as it fights biologicals and UV, but the CYA stays and builds up. It doesn't take long to have too much CYA for the chlorine level, and you get an algae bloom.

Without proper testing it's difficult to say if you are slightly out of CYA/chlorine balance or if your CYA is sky high.

I can tell you this, you would be better serviced if you stopped the tablets and switched to sodium hypochlorite, (bleach, plain bleach, no scents and not a splash free bleach). Sodium hypochlorite, chlorine gas and salt water chlorine generators are the only three ways to add chlorine to your pool without also adding CYA or calcium. In the US, sodium hypochlorite can be purchased at pool stores, hardware stores, grocery stores, some farm stores and some department stores, I can't tell you where you might find it in France. Chlorine gas is not readily available to home owners in the US due to the toxicity. A Salt Water Chlorine Generators is my preferred method to sanitize the pool, but at least in the US, there is significant up front cost associated with SWG.

A SLAM is the best way to rid your pool of algae, but without a good supply of sodium hypochlorite , and a proper test kit, you would be operating in the dark, never knowing if you have too much CYA for the chlorine level. Dumping large amounts of sodium hypochlorite, without proper testing may eventually wipe out the algae, but dump and pray is not a good strategy, you could cause damage to the pool and equipment if chlorine levels get too high, and you would never know what your target levels should be, again dump and pray is not recommended.

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

Algae is always caused when chlorine levels are too low for the CYA in the pool, CYA management and chlorine levels are the key to preventing algae. You always want to maintain your chlorine levels at 7.5% to 10% of your CYA level. So if your CYA level is 50ppm, then 7.5% would be 3.75ppm free chlorine & 10% would be 5ppm free chlorine.

 

[PoolStored]

In France, you can get these two kits on Amazon. Together, they are the equivalent of the Taylor K-2006.

Fas-DPD test

Taylor K-2005

 

[PJinFrance]

Thanks I’ll get reading! We go between France and UK, so cover pool when not here and winterise in November. I am searching for thé recommended test kits, don’t think they’re available here in France or UK. Will keep trying. I have 7 in 1 strips atm. We sanitise with chlorine multi-function tablets and chlorine shock tablets when required. Have struggled to balance ph and alkalinity levels lately and lost faith in the more simple test strips hence bought the 7 in 1!

I live in france and managed to buy the Taylor K-2006 kit from a spanish pool shop - reasonable price of 169 euros.

Taylor K-2006 multiparametric analyzer test kit

• High precision test.• Chlorine determination by DPD-FAS method• Determines up to 8 water parameters.• High quality reagents.• Supplied in a plastic case.

piscinasyproductos.es

 

[Wendypoolboss]

I live in france and managed to buy the Taylor K-2006 kit from a spanish pool shop - reasonable price of 169 euros.

Taylor K-2006 multiparametric analyzer test kit

• High precision test.• Chlorine determination by DPD-FAS method• Determines up to 8 water parameters.• High quality reagents.• Supplied in a plastic case.

piscinasyproductos.es

Hi PjinFrance!
Thank you for replying. This is good news, and I’m sold on this whole method, but still getting my head round the upfront cost of a kit! I do intend to get one though. Of more immediate concern, however, is the fact that we are leaving for the UK next Wed so I don’t have time to order the kit and do any treatment process. For now I need to think of damage limitation. We return later in Autumn to winterise it. As you know, we have water restrictions here and even draining down a third and topping up to dilute might be a no-no. I need to look into that.

 

[Wendypoolboss]

In France, you can get these two kits on Amazon. Together, they are the equivalent of the Taylor K-2006.

Fas-DPD test

Taylor K-2005

Thank you! Good to have fellow pool owners in France.My immediate issue is not having enough time to order and do any chemistry adjustments before we head back to UK next Wed. . Whether it is ok to leave the sorry, toxic mess or try to dilute it at least. I must look into restrictions as I have already ‘topped-up’ twice this summer. SAUR will be on to me!!

 

[Wendypoolboss]

With the testing methods at your disposal, unfortunately test strips are extremely inaccurate, unless you can get a test kit we won't know exactly what you need to correct your water chemistry.

We also don't believe pool store testing, but I believe that they are on the right trail, your CYA is probably high due to the use of chlorine tablets, which increase the CYA along with the chlorine. The tablets dissolve and put chlorine and CYA in the pool, the chlorine breaks down as it fights biologicals and UV, but the CYA stays and builds up. It doesn't take long to have too much CYA for the chlorine level, and you get an algae bloom.

Without proper testing it's difficult to say if you are slightly out of CYA/chlorine balance or if your CYA is sky high.

I can tell you this, you would be better serviced if you stopped the tablets and switched to sodium hypochlorite, (bleach, plain bleach, no scents and not a splash free bleach). Sodium hypochlorite, chlorine gas and salt water chlorine generators are the only three ways to add chlorine to your pool without also adding CYA or calcium. In the US, sodium hypochlorite can be purchased at pool stores, hardware stores, grocery stores, some farm stores and some department stores, I can't tell you where you might find it in France. Chlorine gas is not readily available to home owners in the US due to the toxicity. A Salt Water Chlorine Generators is my preferred method to sanitize the pool, but at least in the US, there is significant up front cost associated with SWG.

A SLAM is the best way to rid your pool of algae, but without a good supply of sodium hypochlorite , and a proper test kit, you would be operating in the dark, never knowing if you have too much CYA for the chlorine level. Dumping large amounts of sodium hypochlorite, without proper testing may eventually wipe out the algae, but dump and pray is not a good strategy, you could cause damage to the pool and equipment if chlorine levels get too high, and you would never know what your target levels should be, again dump and pray is not recommended.

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

Algae is always caused when chlorine levels are too low for the CYA in the pool, CYA management and chlorine levels are the key to preventing algae. You always want to maintain your chlorine levels at 7.5% to 10% of your CYA level. So if your CYA level is 50ppm, then 7.5% would be 3.75ppm free chlorine & 10% would be 5ppm free chlorine.

Hi again,
Can I just ask, is there any possibility of metal contamination? Someone has suggested I get the water tested for that, but it’s now too late because we are leaving the pool for a couple months before coming back to winterise later in Autumn.
Also, we used a linseed oil/turpentine mix to treat the surround boards and were obviously very careful but it did rain about 24hrs later and I also saw a slightly oily surface which I blamed on swimmers wearing sun cream. Could this have any bearing on the issue?

 

[Wendypoolboss]

I realise it must be frustrating not having accurate test results to base your advice on. My main problem is now a time issue, so could you please advise - will it be damaging to liner to do nothing for two months, as we have to go back to the the UK? If the Cya level is high and the chlorine gradually breaks down, I suppose algae will develop further, but I could deal with that if when I return armed with a super duper kit! As a point of interest, the pool is not changing colour- it’s as if there is stand-off between the cya and the chlorine.!! You would expect it to go darker green gradually wouldn’t you? and for me to see clouds of darker green when I brush, but neither is happening! I don’t see anything through the bright green as I brush! I am running pump to stop it totally stagnating, even though the pool store said no use having it running ??

 

[PoolStored]

I think the best you can do is add 5ppm of liquid chlorine, PER DAY, while you are gone to keep the algae at bay and deal with it when you come back.

 

[Wendypoolboss]

I think the best you can do is add 5ppm of liquid chlorine, PER DAY, while you are gone to keep the algae at bay and deal with it when you come back.

Thank you for your advice. By liquid chlorine do you mean regular bleach? Also could you please say how much liquid chlorine per 10m3 ? I’m not understanding ppm. Thanks in advance!

 

[PoolStored]

Yes, regular bleach. Pool liquid chlorine if you can get it. I think we have some translation error...do you mean 10,000 square meters? 10m3 is 107 gallons. What is the total volume of the pool please and I will give you quantity.

 

[Wendypoolboss]

Yes, regular bleach. Pool liquid chlorine if you can get it. I think we have some translation error...do you mean 10,000 square meters? 10m3 is 107 gallons. What is the total volume of the pool please and I will give you quantity.

It is 30m3 which I think equates to 30,000l or 8000gal.

 

[PoolStored]

83 ounces of 6% Bleach will add 5ppm. So add 83 ounces will add 5ppm to your pool.
10% Liquid chlorine would take 50 ounces.
12.5% would take 40 ounces.

This addition should be made daily.

 

[drsipe]

Since you will soon be leaving for the UK, and you will return not return until autumn, who takes care of the pool while you are away?

I can't say that leaving the pool as is and letting the algae continue will cause irreparable damage, one thing that can happen is that once all the chlorine is depleted, a bacteria can consume the CYA and the breakdown of CYA creates ammonia, and to clear the ammonia requires 10ppm of chlorine to oxidize 1ppm of ammonia.

There is a method of reducing CYA without draining, but I don't know if it's available in France. I live in the eastern US and I have never heard of it being used here (water is too cheap), but in the western US, they use reverse osmosis. Reverse Osmosis processes your water, removing dissolved solids like CYA and calcium. This could be great benefit for you. The process is done by specialized contractors in the US.

If you can't get Reverse Osmosis and you are running out of time,,,,,this goes against a lot of what this site tries to teach, you are in a situation where you do not have the time to correct your pool chemistry. You might want to consider hiring a pool maintenance company, they probably won't follow the TFP methods, and they will likely dump chemicals in we don't use, but maybe, just maybe they can fix your problem.

 

[Wendypoolboss]

83 ounces of 6% Bleach will add 5ppm. So add 83 ounces will add 5ppm to your pool.
10% Liquid chlorine would take 50 ounces.
12.5% would take 40 ounces.

This addition should be made daily.

Thank you very much for the trouble you are taking. This is very informative.

 

[Mdragger88]

If you’re leaving & there’s no one to care for the pool while you’re away you may just leave it alone until you return armed with a kit, liquid chlorine, & time. I do suggest that in the future for a vacation pool you consider adding a swcg to do the dosing for your while you’re away after you get it cleared up & possibly enlisting a service to check on it occasionally & adjust ph while you’re away.