Blue cloudy water with no chlorine reading after double shock

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  • Last Post 23 June 2021
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Suresh posted this 09 June 2021

Hello Experts,

My pool turned green and then pool store recommended to double shock the pool and run clarifier. I did and pool turned blue but very cloudy and I dont get chlorine reading. I did brushing and also put algaecide but still pool is cloudy. Here is my current reading. Please advice. 

 

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JCMC70 posted this 09 June 2021

When did you double shock the pool?

Do you have a test kit?

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Suresh posted this 09 June 2021

I did last weekend and yes I have test kit. I didnt see any chlorine so went to pool store to confirm. Attached screenshot is after the double shock and 24 hours after running clarifier. 

JCMC70 posted this 09 June 2021

What kind of test kit do you have?

Have you put any chlorine in since last weekend?


 

Suresh posted this 09 June 2021

I have one with paper strips and also liquid one. I tested in both. I was hoping after double shock my chlorine level will go up but it didnt. So pool store asked me to use chlorine stablizer i.e. chloring tablets to increase the chlorine levels. RIght now i have chlorine tablet in floater since yesterday, i left it overnight and tested this morning but still no chlorine and its getting cloudier.

JCMC70 posted this 09 June 2021

Your stabilizer level (according to the pool store number) is fine and you don't need any more unless you are using a SWG to produce chlorine.

If your pool was green you have algae growing and one shock isn't gonna do it...but you don't need to double shock the pool.

I'm assuming the chlorine tablets are Trichlor. Is that correct?

Tell me what kind of shock you used to shock the pool...Cal-hypo, Dichlorvos, Trichlor, Lithium-hypo?

Tell me how you normally chlorinate the water...Automatic chlorinator, Tabs in floater/skimmer, Granular chlorine (if so what kind), liquid chlorine 

Have you run the filter continuously since you shocked the pool?

what type of filter do you have?

Suresh posted this 09 June 2021

Here is the shock I used;

https://clubpiscine.ca/fr/produit/super-choc-hth-extra-15kg

Yes i am runing filter continously.

Its sand filter

chlorination is done via Tabs in skimmer.

I will confirm the chlorine tablets in some time. I forgot the brand name.

 

 

 

JCMC70 posted this 09 June 2021

Sorry but I don't read Spanish. Please look at the Active Ingredient on the bucket and tell me what kind of shock it is 

JCMC70 posted this 09 June 2021

Actually, I figured it out. The hth extra is 75% calcium hyperchlorite.. Now I just need to know what type of pool you have, (Vinly, plaster/gunnite, concrete, fiberglass) and how many gallons of water it holds.

The pool volume is probably on the printout that you got from the pool store when they tested the water.

Suresh posted this 09 June 2021

It above the ground pool, you can refer to this link its traditional one. Sorry, I dont know the technical names so refering you to link below.

https://blog.countryleisuremfg.com/types-of-above-ground-pools

And mine is 10000 Gallons pool.

I really appreciate your help.

 

Suresh posted this 09 June 2021

Suresh posted this 09 June 2021

Just to give more context, the pool is in this state after we opened pool for summer. It was closed all the winter.

Suresh posted this 09 June 2021

If you need any additional info please let me know. 

JCMC70 posted this 10 June 2021

Thank you. You have a vinly liner pool. And the 42502 liters is a little over 11000 gallons of water.

You can start this in the morning. Let the pump run all night and if it needs to be backwashed in the morning, do that first.

 

NOTE: The amount of 75% Cal-hypo needed to shock your pool is 16 ppm.

 2oz of 75% shock will raise the chlorine level in your pool by 1 ppm.

Then: 

  • Take the tablets out of the skimmer
  • If the pump isn't running, turn it on and let it run continuously until the pool is clear, backwashing the filter when the pressure indicates that it should be backwashed.
  • Using the test kit that has liquid reagents, get a fresh chlorine number.
  • Subtract the number you got from 16
  • Multiply that number by 2. This will give you the total amount of shock in ounces you need to add to the pool to get the chlorine to 16 ppm.
  • Dissolve the chlorine in a big bucket of water and pour it in the pool in front of the return 

After 2-3 hours, vacuum the pool, backwashing the filter when the pressure says you should.

In the evening, brush the pool walls. Then take a new chlorine reading, subtract that number from 16, multiply that number by 2 and add that much chlorine to the pool.

The next morning, take a fresh chlorine reading, bring the chlorine level in the pool back to 16 and start the cycle all over. This will make sure all of the algae and any other organics are killed.

Vacuum the pool daily, in the morning, and brush the pool walls daily, in the evening. This will clear the pool up.

When the chlorine reading you take in the morning is 1 ppm or less than the chlorine reading you took the night before, and the water is clear, you are done shocking the pool.

At this point you should be able to run the pump on it's normal cycle, let the chlorine level fall back to the 3-5 ppm range and put the tablets back in the skimmer.

If you have any questions let me know 

J

Suresh posted this 10 June 2021

I really thank you for your advice.

I have one question. How to get the reading for chlorine. Is there testing kit to give the number ?

'When the chlorine reading you take in the morning is 1 ppm or less than the chlorine reading you took the night before, and the water is clear, you are done shocking the pool.'

so for my understanding when my morning reading is almost same as night with difference of 1 ppm reading this shocking is done correct ?

 

" let the chlorine level fall back to the 3-5 ppm range and put the tablets back in the skimmer."


how will chlorine falls back to 3-5 because last morning of this activity it will be 15ppm... do I need to drain the water ?

And vacuum can I use robot vacuum ?

 

 

 

Suresh posted this 10 June 2021

Suresh posted this 10 June 2021

This is liquid one I have... could please recommend which one to use to get reading of 16ppm

JCMC70 posted this 10 June 2021

Ideally, you need a test kit like the Taylor K-2006 or the TF100 FAS/DPD test kit. They will measure chlorine up to 50ppm.

How high does your test strips go?

Suresh posted this 10 June 2021

Strips can read upto 10PPM.

JCMC70 posted this 10 June 2021

Sorry, I didn't see your other questions.

"I have one question. How to get the reading for chlorine. Is there testing kit to give the number ?"

As I already stated, the Taylor K-2006 or the TF100 test kits will detect chlorine up to 50 ppm.

"so for my understanding when my morning reading is almost same as night with difference of 1 ppm reading this shocking is done correct ?"

And the water is clear. That's where vacuuming the pool every day comes in. That will clear the dead organics.

"how will chlorine falls back to 3-5 because last morning of this activity it will be 15ppm... do I need to drain the water ?"

You simply stop adding chlorine to the pool until the chlorine falls back to the normal 3-5 ppm level. Then you resume your normal chlorination method. No need to drain water.

"And vacuum can I use robot vacuum ?"

Yes you can, but be mindful of what kind of filters you have in the robot. Most robots come with 2 kinds of filters. The zig-zag or "fan" looking filter will catch bigger particles like leaves, bigger pieces of dirt an debris. The fine mesh looking filters will catch smaller particles like dead algae. So if you're using the fine mesh filters, check them periodically to make sure they aren't clogged.

As you vacuum, what the filter doesn't catch wil be suspended in the water. The filter will catch part of this but sand filters only filter particles down to about 20 microns in size.

To help the filter you can put what is called a "sock" over the skimmer. The least expensive way to do this is to cut the foot part off of a woman' stocking and stretch it over the top of the skimmer basket. But you must check the sock regularly because the dead algae will clog it and reduce water flow to the filter. When you see that it's pretty covered, simply take it off, wash the gunk off of it and put it back on.

Pool supply companies sell a product called a skimmer sock. But if you decide to purchase a skimmer sock just be sure it will fit the smaller skimmer basket that most above ground pools have.

As for buying a test kit that will test for high chlorine levels, the only other suggestion I have would be to take a water sample into the pool company twice a day, once in the morning and again before they close in the evening. But be prepared for them to try to sell you additional chemicals (that you probably don't need)

J

Suresh posted this 10 June 2021

Thank you very very much.

One last question how did you come up with 16ppm. Just curious to understand the logic. Once again thank you for your time and expert advice.

JCMC70 posted this 10 June 2021

It has long been known that there is a relationship between chlorine and the stabilizer (CYA) in pool water. People in the industry put this relationship in a chart years ago. It's called the Chlorine/CYA Chart.

You can read all of the information about this and see the chart in This InyoPools article.

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Suresh posted this 12 June 2021

Hello JCMC70,

I did exactly like you mentioned. I vacuumed and brushed added chlorine of 32Oz in morning, since chlorine was zero and again tested now in evening it again became zero added another 32Oz.... I don't know how many times I need to repeat it and I am just worried too much chlorine won't damage the pool.... I also added skimmer sock.... let me know if this is normal....

 

 

Suresh posted this 12 June 2021

that it's coming back to zero....

JCMC70 posted this 13 June 2021

If the chlorine is falling to 0, then the chlorine is still killing the organics. It isn't hurting the pool, it's killing the organics.

Are you still using the same testing kit?

Is the filter running continuously?

In the morning, take a new chlorine reading and bring the chlorine back to 16 ppm. wait 1 hour, with the pump/filter running and test the chlorine again. If the chlorine reading is back to 0, something is wrong with your test media and you really should get a good test kit.

 If it still shows a chlorine reading, wait 2 more hours, test again and adjust the chlorine from that reading (there should still be some chlorine in the water). If there is still some chlorine in the water after the 3 hour period, but not in the evening when you take the reading, what that is telling us is that we need to change the time frame for shocking the pool.

This is what should happen...the chlorine level should be kept as close to the shock level as possible all the time until the water clears. Normally this is done by taking a chlorine reading every three hours and adjusting the shock level. Two factors control this. 1. Your schedule and 2. Your test kit.

If your schedule will allow you to take chlorine readings every 3 hours, half of the issue is solved. But without an accurate test kit it's possible that you could over chlorinate the water.

For example, say tomorrow morning the chlorine level is 0. You shock the pool back to 16 ppm and wait an hour and test again. Let's say that the chlorine strip at that test shows 10 ppm(because that's as high as it will go). So you wait 2 hours and test again and the strip shows 5 ppm(because there isn't a gradient between 5and 10 ppm). That would indicate that the chlorine level had dropped 11 ppm in 3 hours. I highly doubt that. The chlorine consumption is likely 1 to 2 ppm per hour. If the consumption is as high as 2 ppm for 3 hrs, there is still 9 ppm of chlorine in the water. So if you add the 11 ppm of chlorine back to the water (because the strips said you only have 5 ppm) but there is actually 9 ppm in the water, you actually end up with 20 ppm.

Can you see how that could get out of hand?

The bottom line is, you're gonna need to adjust the chlorine level more often than once in the morning and once in the afternoon. But without an accurate test kit it's entirely possible that you will over chlorinate the pool.

J

Suresh posted this 13 June 2021

Like you said I am going to water test centre morning and evening to get accurate reading. Today morning from yesterday night addition, when I test there was chlorine around 3ppm but then it became zero quite fast. I am not relying on test strips only if it Show zero. When test strip shows zero even at test centre is zero. I can rely zero on test strips but gradient I am confirming with test centre to maintain right reading. Will try tomorrow testing every one and 2 hours and let you know. Thanks

Suresh posted this 13 June 2021

And yes filter is running 24hours and with socks tomorrow water should be clearer. At water centre they recommended to use oxidizer but I didn't buy. Do you think it's worth trying ?? Already used 3kgs of chlorine super sock going back to zero is bit strange. At 11 am I made it to 16ppm and at 5 or 6 pm in evening it became zero.... isn't it strange ?

Suresh posted this 13 June 2021

And this is vaccum I used today 

https://www.poolsuppliescanada.ca/hayward-wanda-the-whale-automatic-above-ground-cleaner.html

is uses pool filter. May be my sand filter isn't filter dead algae so my pool is still cloudy.

JCMC70 posted this 13 June 2021

"At water centre they recommended to use oxidizer but I didn't buy. Do you think it's worth trying ?? "

Sounds like they're trying to sell you another kind of chlorine...all sanitizers disinfect pool water by oxidation. So I don't think it's worth it.

"At 11 am I made it to 16ppm and at 5 or 6 pm in evening it became zero.... isn't it strange ?"

Not really. If the organics are eating 2 ppm or so of chlorine per hour, that's 12 ppm. And given the unreliability of strips and pool store testing, I don't think it's strange. The only way to know for sure is to get an accurate test kit.

"And this is vaccum I used today 

is uses pool filter. May be my sand filter isn't filter dead algae so my pool is still cloudy."

Ok. That isn't a robot. It's a suction side cleaner. And you are partly right. The filter is catching some of the particles, but remember sand filters only filter particles down to about 20 microns. So it takes longer with a sand filter. But that's where the skimmer sock comes in. 
How often are you having to clean the sock?

How often are you having to backwash the filter?

If you keep vacuuming and brushing every day and keep the chlorine level up consistently, the water will clear eventually.

Suresh posted this 13 June 2021

I got sock today I will see how much spoiled tomorrow morning... for back wash pool store person said to do it only if pressure goes above 20 on meter. So far I have back washed 2 or 3 times in 2 months...

Suresh posted this 13 June 2021

I didn't do much on pool last month...

JCMC70 posted this 13 June 2021

"for back wash pool store person said to do it only if pressure goes above 20 on meter."

That depends on what the starting pressure is when the filter has been freshly backwashed.

Can you see the bottom of the pool?

Suresh posted this 13 June 2021

No I can't see it yet, today I was able to see skimmer which wasn't visible earlier.... may tomorrow it will be better... but it improved a bit...than yesterday 

JCMC70 posted this 13 June 2021

I just went back and looked at the picture of your post you posted earlier. It appears to be partially in the shade.

Are there trees near the pool?

is it possible that there are decaying leaves on the bottom of the pool?

Suresh posted this 13 June 2021

Yes there are 2 big trees.... leaves keeps falling all the time , I try to keep it clean but I think there could be leaves twigs and pollen on the floor.... I vacuumed today morning also manually now running the suction one. Today morning there was shade on strip.... and I could see floor in some places now with vaccum it became cloudy again....

JCMC70 posted this 13 June 2021

"I try to keep it clean but I think there could be leaves twigs and pollen on the floor."

That certainly helps explain the rapid chlorine loss. If those leaves are matted to the floor, they need to be dislodged and removed.

You said you vacuumed manually this am. Does that mean you have a manual vacuum head? If you do, attach the vacuum head to the skimmer pole without the hose and go back and forth over the bottom, putting moderate pressure on vacuum head and try to dislodge the stuck leaves. As they float to the top, dip them out with the dip net.

Suresh posted this 13 June 2021

Yes, I have vaccum head. I didn't understand attaching  without hose .... there hose connected vaccum head and telescopic pole to direct the vaccum head.... can I get into water it will be easier... will send the reading in few mins

Suresh posted this 13 June 2021

In

Suresh posted this 13 June 2021

Here is current reading .... it retained over night 

JCMC70 posted this 13 June 2021

Attach the vacuum head to the pole but don't attach the vacuum hose to the head or the skimmer. The goal is to dislodge and decaying leaves that are stuck to the bottom of the pool, not to vacuum. And yes, getting in the pool will allow you to put more pressure on the vacuum head as you scrub it back and forth on the bottom to dislodge stuck leaves. As you walk around the pool you might even be able to feel the leaves with your foot.

Chlorine remaining in the pool overnight means we're making progress.

Suresh posted this 13 June 2021

Ok got it, I have brush bigger one  I will use that to dislodge the leaves. Chlorine is bit more than 3ppm is it ok to get into pool ?

JCMC70 posted this 13 June 2021

Yes. It's actually ok to get in the water with chlorine up to the shock level.

Let me know how it goes.

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Suresh posted this 13 June 2021

I just finished cleaning the pool but I didn't find single deal leaf. I walked around pool multiple times and floor was rough not even single slippery spot. I also brushed multiple time walls,  floor etc there is lots of dead algae so it became more cloudier now but no dead leaves or twigs or anything else from tree. So we can eliminate that part.... will check the chlorine in evening and bring it to 16ppm and run vaccum all night... do you think it's good idea to remove dead algae...?

JCMC70 posted this 13 June 2021

"do you think it's good idea to remove dead algae...?"

How do you mean?

Suresh posted this 13 June 2021

Sorry I meant bringing back 16 ppm and running vaccum all night to remove dead algae ?

JCMC70 posted this 13 June 2021

Yes, you keep the shock level at 16 until it only falls by 1 ppm overnight and the water is clear,

When you say running the vacuum all night, do you mean running the filter all night?

Suresh posted this 13 June 2021

I meant keeping that suction side vaccum cleaner inside the pool... 

JCMC70 posted this 13 June 2021

I wouldn't. Because when the vacuum is running you have to remove the skimmer. The sock is on the skimmer. So if you run the vacuum you lose the filtering enhancement of the skimmer sock. So I would run the filter all night and while I was vacuuming tomorrow I would clean the sock and when I finished vacuuming, put the skimmer with the sock on it back in and let the filter run.

Suresh posted this 14 June 2021

Actually I found a way to have skimmer with sock while vacuuming. I have plate which sit on top of skimmer, this was from my manual vaccum... i put that to my suction vaccum this morning... it did work well with good suction and it blocked  lots of stuff.... but I agree to run filter without vaccum all night so that we have good circulation of water...

Suresh posted this 14 June 2021

Also I think pool is clean in terms of green algae....dead ones is still there but green ones are not there and these are ones which consumes chlorine... could there be any other reasons for chlorine loss... l read something regarding nitrogen or phosphates... should we consider that ? Please advise I saw in pool store report they didn't test for phosphates....

JCMC70 posted this 14 June 2021

The only things I know of that consume chlorine are organic contaminates (dirt, twigs, leaves, algae, body oil, sun tan lotion...) and sunlight. So if you are losing more than 1 ppm of chlorine overnight (when there isn't any sunlight) the chlorine is still oxidizing/killing contaminates in the water. As more contaminates get oxidized you will notice that it takes less and less shock to keep the chlorine level at 16 ppm. When it gets to the point where the difference between the final chlorine reading you take in the evening and the reading you take early the next morning is 1 ppm or less and the water is clear all contaminates/organics have been oxidized.

It took longer than 4 days for the pool to get in this shape and it will take more than a few days to correct the issue. Keep doing what you're doing:

  • Let the pump run continuously.
  • Take a chlorine reading as early in the morning as you can and adjust the chlorine level.
  • Take readings every 3 to 4 hrs if possible and adjust the chlorine level.
  • Take a final reading in the evening as close to sunset as possible and adjust the chlorine level.
  • Vacuum the pool daily preferably in the morning.
  • Brush the pool daily preferably in the evening.
  • Clean the gunk off of the sock when needed.
  • Backwash the filter when needed.

And if you haven't backwashed the filter since we started this, go ahead and backwash it so you can see how green the water is.

As for phosphates, phosphates are a source of food for algae. A phosphate remover will remove a food source. But the algae still has to be killed. So you still have to use chlorine to kill the algae. If the algae is dead it doesn't matter whether there is a food source in the water or not. It's like having a mouse in the house looking for food. You can either remove all the food sources and hope the mouse gives up and goes somewhere else or you can remove the mouse and end the problem.

Suresh posted this 14 June 2021

Yes water pressure was down so I back washed and water was clean not green and when I rinsed it was same. I will continue the steps you mentioned.

Thanks

Suresh posted this 15 June 2021

I am still following the steps. Water is getting better slowly.... it's raining not much sun so chlorine is sustained bit longer... I could see pool floor in some places...

JCMC70 posted this 15 June 2021

Good. That's what's supposed to happen. The water should look a little better each day. And one morning you will go out to take the morning reading and it will be clear.

When algae first blooms and there is only a green tint to the water it can take days to kill it and clear the water. Once the algae turns the water full green and you can't see the bottom, it takes a lot longer.

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Suresh posted this 17 June 2021

The water is getting better day by day and i can see floor in most places but still 16ppm is consumed with 15-16 hours. Is it normal?When I bring pool to 16ppm in evening since there is no sun more ppm is retained by morning but by the evening everything comes back to zero.I am waiting for my test kit to take early morning reading. I want to know average consumption of chlorine when there is no issue. And if i get into this situation again i should bring stabilizer to proper range between 30 and 60 and then based on that reading, i should find the ppm based on chart to shock the pool. I mean this time it was 16ppm because my stabilizer was around 40.Is my understanding correct? 

 

Service posted this 17 June 2021

Suresh and JCM,

You guys are awesome! I would love to see some before and after photos if you get a chance please post. Also not sure if you saw our Video on How to Clear a Green Pool (SLAM) which you may find helpful.

Thank You

Patrick

www.inyopools.com

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Suresh posted this 22 June 2021

Thanks a lot JCM water is crystal clear now. Thanks for your advice and clarifying all my doubts. Thanks Patrick for sharing the video it's helpful.

JCMC70 posted this 23 June 2021

That's good to hear and you are welcome.

For your earlier questions:

" I want to know average consumption of chlorine when there is no issue." It depends on the level of chlorine you maintain in the pool. For a pool with 40 ppm of stabilizer the minimum chlorine level is 3 ppm with the ideal range between 5 and 7 ppm. I keep the chlorine level at 5 ppm. Some nights it has gone down to 4 ppm, some nights 3.5, some nights 3 and occasionally 2.5. This is dictated by how many hours of full sun the pool gets, how hot it gets, how much debris blows into the pool, bather load, etc.

On average you can figure 1 - 2 ppm per day. If you keep the level at the minimum and the circumstances are right, it's possible that the water could consume all the chlorine in a day and when that happens you risk another algae bloom.

"And if i get into this situation again i should bring stabilizer to proper range between 30 and 60 and then based on that reading, i should find the ppm based on chart to shock the pool. I mean this time it was 16ppm because my stabilizer was around 40.Is my understanding correct?"

Correct. But if it happens again you could also just take a stabilizer reading and adjust the shock level to that new reading 

And remember this. If you continue to use Trichlor tablets, each table adds about 3 ppm of stabilizer to the water so it won't take long until you reach stabilizer levels that aren't recommended.

Good luck

J

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