Green Pool After Adding Liquid Shock

by Tina

I ran out of pool tabs and pool looked a little cloudy. I added the tabs and then shocked, the water turned a green. Not the kind of green with algae but green all the same.

I took a sample to the pool store the next day. They said the chorinator was set to high and to turn it down. That did work. I had it happen again a few weeks later.

I have a vinyl pool about 35,000 gallons. It's a new filter just a year old. Any suggestions would be great, I've just never had this happen in the six years we've had the pool.

I had to get it tested here are the numbers

free chlorine 0.1 ppm
ttl chlorine 0.19
combined .09
ph 7
hardnes 90 ppm
Alkalinity 60 ppm
cyanuric acid 40 ppm
copper 0.2 ppm
iron 0.2 ppm

I was not at home and my tabs were out, pool was a little cloudy. I added tabs and added shock. After adding the shock the pool turned green. It happened fairly quickly.

Thanks for the question Tina

Alright, we have the readings. Are you on well water or a source of water that has metals? Also, are you using calcium hypo to chlorinate or shock the pool? The original question says you shocked the water and it turned green, not algae green, but green all the same. Is it an emerald green? If so this is caused by metals in the water and the clear green is caused by a chemical reaction to the cal hypo and metals.

I also see the metals were tested. You need to get a good metal sequestrant. Metal sequestrants that are based on HEDP, phosphonic acid and/or its derivatives are the most effective. Some popular brands are Jack's Magic Blue, Purple, and Pink Pink Stuff, Metal Magic, Metal Free, & Metal Klear.

This is normally not a one shot deal. A metal sequestrant does not remove metal from pool water. It holds it in solution until it can get filtered. Then you backwash the metal out. Because metal sequestrants break down over time and get filtered and backwashed out, you will need to add a bottle once per week.

The TA and pH are just a touch low but easily remedied. It's 1lb sodium bicarb (baking soda) per 10k to increase the TA 10ppm and the pH 10.2. Start with 2 lbs. around the perimeter of the pool, sweep, FILTER for 10 hours then retest the TA and pH and make another adjustment if needed. The TA range is 80 - 100ppm and the pH is 7.4 - 7.8. For salt pools you can go a bit lower on the TA but it's not a big deal right now. Do not go to the pool store and get any pH or TA Up. It's the same thing as baking soda only with a 200% mark-up.

Two hours after making the TA adjustment you'll want to shock the pool with liquid chlorine (CL). That's 1 gallon per 10k so you'll use 4 gallons. Broadcast around the perimeter, sweep, FILTER for 10 hours. The CL is a bit low and you may be on the verge of an algae bloom. Remember to turn the CL cell OFF when shocking. Don't use cal hypo, only liquid chlorine.

Get a good test kit. I use and recommend the Taylor K-2006 kit. You can learn about it starting with this video:

Ease up on using tabs. They're Trichlor which means not only will they reduce the pH and TA due to the acid content but it'll increase the CYA. The range for that is 30 - 50ppm. For every 10ppm of chlorine added with Trichlor tabs you'll raise the CYA by 6ppm.

With a CL cell you can dial it in for the amount of CL you need. Be sure the salt level is correct.

If you want to use an algaecide only use a PolyQuat 60. It's safe for vinyl liners and doesn't contain metal. Many other brands use a metal base for the algaecide. Be careful of them and read the ingredients. You don't want to be adding more metals into the pool.

If you feel your situation is more complex than this, I do phone consultations for a donation of your choice. It makes things go much faster and many people have found it extremely beneficial, saving them time and money in the long run. All your questions will be answered. I have nothing to sell you so you know I'm not bias.

Pool Consultation

Hope this helps and have a great Summer.


Comments for Green Pool After Adding Liquid Shock

Average Rating starstarstarstarstar

Click here to add your own comments

Aug 16, 2016
Pool turns green after super chlorinating
by: Rene

I have a 14 by 31 fiberglass pool that is approximately 14000 gallons. No heater. Last check: Cyanuric Acid - 45 PH - 7.2 Total Alkalinity - 100 Chlorine - 0

About a month and a half ago I noticed pink spots on the wall of the pool. Upon recommendation of my local pool store I used Pink Treat.

I followed the bottle and added 2lbs and immediately superchlorinated the pool. However, upon adding the chlorine my pool turned green. By morning it was clear. I have been superchlorinating ever since and water turns green immediately and is clear the next morning.

I visited my pool store and they said to add algaecide and keep adding 4 lbs of shock until it clears. Still turns green when adding chlorine. Frustrated, I searched on line and saw that there may be metal in the pool, so I used Metal Magic. Pool is still turning green after adding chlorine and now I have what looks like white sand on the bottom of the pool.

Also when backwashing it is milky white. In addition the pool will not keep a chlorine reading. Any recommendations would be greatly appreciated.

Hi Rene. Green water after chlorinating is normally a sign of metals in the water, as you said. You should test to confirm that.

4 lbs. of chlorine will treat a 40k gallon pool. That's too much for your size pool. You need to stop using all kinds of granular chlorine and stick with liquid chlorine. That will handle 99% of your needs.

A pool that doesn't hold chlorine can either mean low CYA, high pH, and/or much organic matter in the pool. Your readings are good. I would suspect it's organics in the pool that eating up the chlorine.

ProTeam Metal Magic is a good product.

The white sand could be sand going back into the pool, if you have a sand filter. That's normally a broken lateral. If not, then it could be the granular chlorine you're using. This is normally part of using calcium hypochlorite. Again, stop with that and use liquid chlorine.

White water while backwashing means the whitish dirt is being backwashed out.

Please remember that I also offer eBooks and phone consults that go into greater detail than a single email can.

Clear Blue Pool eBook
How To Clear Up A Green Pool eBook
Personal Phone Consultation


Click here to add your own comments

Return to Green Pool Water.

14,000 Gallons Of Creek Water..Turned Brown Then Green

by Jeff Ritchie
(Hazard, KY)

We live in country, no city water, no one would bring in water for us. We rented a pump and pumped our new pool full. Intex 16' x 32' x 52". I'm sure when we added the shock it, it attached to the iron in the creek water and turned it brown.

Then added some metal out, should of probably did that in reverse order, but didn't know at the time. After metal out, been filtering with a towel in skimmer and socks over the outlet hose, getting as much of iron out as possible

Been doing this for 3 days cleaning filters every 2 or 3 hours. Also added some clarifier, pH down to get my levels where they supposed to be. Chlorine level is very high and pH is perfect. Can see the bottom and some stuff on the bottom, which I think is the iron particles. The water is now a green color?

Is their anything else I should be adding or doing to help clear up quicker? Chlorine is 5.0+ and ph is 7.2. Help please!

Thanks for the question Jeff

If I'm reading the question correctly, after you chlorinated the water turned brown, then green. I was wondering if it was an emerald green? If the water turns this color after chlorination, 99 out of 100 it's a high metal problem. You'll probably need more than 1 or 2 applications of metal sequestrants.

A metal sequestrant does not remove metal from pool water. It holds it in solution until it can get filtered. Then you backwash the metal out. Because metal sequestrants break down over time and get filtered and backwashed out, you need to weekly dose your pool if you have high iron and copper.

Metal sequestrants that are based on HEDP, phosphonic acid or something similar are the most effective. Jack's Magic Blue, Purple, and Pink Pink Stuff, Metal Magic, Metal Free, & Metal Klear are very good. You could be lucky and have the copper and/or iron still hold in solution, being formed into larger particles, and be able to be back washed out.

If it is metal, you're going to need to weekly dose your pool with one of the sequestrants mentioned above. If the metals are still present after a few applications and back washing, you might need to do a 1/2 drain and refill because if you're adding more metals into the pool through the creek, you're going to be fighting this for a long time.

The best thing to do is what you're doing right now. Keep filtering and keep the chemical readings in the correct range. You can find your post in the "Well Water Problems/Iron & Copper" category on the Q&A page:

Swimming Pool Questions and Answers

Hope this helps and have a fun and safe Summer.


Click here to post comments

Return to Green Pool Water.

Pump Not On Yet & Weather Is HOT

by Carina

Usually this time of year we are still decked out with boots and umbrellas, but alas we are in a heat wave. We moved into this house with a 12x24 above ground pool in Dec. So to say we know nothing about the pools cleaning would be an understatement.

The guy at the pool store was in a tizzy that I am going to have algae in a matter of moments with this heat and told me to come in at once to buy shock. He recommended bringing in a water sample. How to clean green pool step by step?

The #'s from my sample are Chlorine 0 ppm Total C .11 ppm PH 7.0 Calcium Hardness 20, alkalinity in pool water 20 ppm Stabilizer ??? ( he didnt have the test stuff for that) TDS 100 ppm Problem is in this one horse town the cannot come turn on my pump/filter and teach me what to do for 8 more days.

I have shocked the pool 2 times now and the test strip goes from dark purple at the time to showing pretty much nothing in the way of chlorine in just a few hours. How to shock a pool with chlorine? I don't have a cloudy pool after shocking.

***Do I shock daily?*** I have been using the very expensive granular shock that he sold me... getting it all to dissolve is a PITA, but I do stir any that falls to the bottom with the brush until it dissolves, partly to protect my liner and partly to stir it around.

I do not have a 5 gallon bucket so I mix it in 5ths in an ice cream bucket and use that. Pool water looks very clear but he has me very worried that it wont last until the tech gets here in a week.

Thanks for the question Carina

Yes, you're going to have algae during Spring opening. Everybody does after they winterize their pools.

I have most of the readings but I need the stabilizer (cyanuric acid/CYA) reading. This is vitally important because there's a direct relationship between the chlorine and CYA. The chlorine must be 7.5% of your CYA. This is basic math and is very easy to understand. The CYA is increased by the use of Trichlor tabs. These tablets have chlorine and CYA in them, so, as you use the tabs the CYA increases, slowly, but it does.

The range for CYA is 30 - 50ppm and the chlorine is 1.5 - 3.5ppm for home pools. As the CYA increases through using tabs, Trichlor tabs, the chlorine needs to increase as well. If you allow the CYA to get to 100ppm, you need to run the chlorine at 7 - 8ppm for the chlorine to be effective.

When the CYA gets this high the only way to reduce it is a partial drain and refill. There's no chemical to reduce the CYA. Let's use common sense. If your CYA is at 100ppm, and the range is 30 - 50ppm, then by draining 1/2 of the water and refilling it you'll drop the CYA to 50ppm.

This is why I need the CYA reading. If it's high, above 70 - 80ppm, you need to do a partial drain and refill. If it's low, below 20ppm, you need to shock with Dichlor.

This is a stabilized form of chlorine. Once you reach the 30 - 40ppm mark, stop with Dichlor and go back to regular liquid chlorine.

If the CYA is high, you're simply wasting time and money shocking the pool. You may clear it up but it will go green again if you don't keep the chlorine high as well. And that's something you don't want to do.

The pH is fine for now. The total alkalinity (TA) is a bit low at 20ppm so you need to increase that. It's 1.5 lbs. of sodium bicarb to raise the TA 10ppm per 10,000 gallons of water. You're probably on the metric system so you may need to convert that.

Let's say the CYA is fine, between the 30 - 50ppm mark. First, increase the TA to 80 - 100ppm. Swimming pool alkalinity levels. Put the bicarb in one spot with the pump OFF. Allow to sit for 3 - 4 hours then turn the pump to FILTER for 8 - 10 hours, then retest and make another adjustment if needed. You can use regular sodium bicarb from the grocery store - Arm & Hammer or a generic brand.

Then shock with regular liquid chlorine. If the CYA is in range you don't need any special super shock. It's a fancy package that they can sell for a 400% markup.

The calcium hardness is mostly for plaster pools, not vinyl, so don't worry about that right now. You can use calcium chloride and increase it to 100ppm or so but that's all you need.

Get me the CYA first we can go from there.

If you'd like personal assistance I do phone consultations for $35 per hour, or what you can afford. You'll get real professional help from a real pool guy and have all of your questions answered.

If you've found this site helpful please consider making a donation. Thank you.

Hope this helps and have a great Summer.


Click here to post comments

Return to Green Pool Water.

swimming pool care, basic pool care, above ground pool maintenance, inground, salt water

Click Here To Learn How This eBook Can Save You TONS Of Time & Money

Click Here To Learn The Best Way To Clear Up Your Pool 

Recent Articles

  1. White Slimy Film On The Bottom Of Pool

    the water was crystal clear but upon skimming the top we noticed a white slimy film completely covering the pool liner.

    Read More

  2. High Cynaric Acid

    My pool is a 26,000 gallon above ground vinyl liner. around 7/31/2014 the cya raised to 113

    Read More

  3. Can Super Floc Remove Pool Algae?

    Will raising the pH level and adding Superfloc get rid of algae?

    Read More