Pool Green - House Going on the Market TOMORROW

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Mar 14, 2010
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This morning, I woke up to a nice blue pool and went into work. At 10:00 AM, my wife called and said that the pool was green, so I drove home and poured in a gallon of 10% liquid chlorine and went back to work. I get home at 6:00 PM, and the pool is still green. The only thing I can think of that makes a pool green is algae, and you use chlorine to kill algae so I added two more gallons of 10% chlorine. My understanding is that as long as you're not swimming in it, it is OK to have really high chlorine temporarily. Hopefully I'm not wrong.

So, we went to eat supper and get home about 90 minutes later. Still green. It's never been this difficult... but Murphy's law and all.

Total Chlorine: 31ppm
Combined chlorine: 1ppm (I've never measured above 1ppm, wonder if my chemicals are not OK?)
CYA: Under 20, above 0. If I had to guess, I'd guess its about 5. Need to add more CYA. I can't keep CYA in my pool, don't know why. We've had a few feet of rain in the last couple of weeks though, that might have something to do with it right now.
Calcium: 240
Alkalinity: 140 (this test did do the blue to yellow shift instead of green to clear)

What else might be causing the pool to be green? 31 PPM is astronomical if you consider my nearly non-existant CYA. Could CYA that low be causing this issue?
 
What Tim is thinking is that the green is possibly due to copper in your water. Copper is used in many algaecides. It can also come from your heater coils if acidic water goes through the heater. Have you put acid (or pH Down) into your skimmer? What is the pH of your pool?
 
Clear green. I've used polyquat 60 about a week ago as I was going to do an ascorbic acid treatment. I've never poured acid into the summer. PH is a bit high right now, and it tends to run high. I think it is about 7.8 from when I tested a bit ago

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Just bought enough liquid cya to get the pool up to 30. Pool store guy tried to sell me copper algaecide, said it takes copper out of the water. Told him I didn't want it. Bought some polyoxyethelynrdimethylimininioethelyne 60. Is this just polyquat 60?

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Actually, I believe high levels of chlorine, with corresponding low levels of CYA, can also strip copper from the heater coils. (Somebody please correct me if I'm wrong.) If you were at 31ppm after adding a gallon of 10%, that means you were at around 23 before, which is extremely high considering your estimated CYA of 5-ish.

But, you are under time constraints, so forget about figuring out what caused it. You probably need to drain and refill tonight. Have your realtor wait until the refill is complete before posting to the MLS.

(I'm hoping your ground water table is low, so you can do at least a 60% drain in one go. If you don't know your water table, best to do a couple partial drains and refills. Perhaps run to the pool store to get some metal sequestrant to bond with the copper.)
 
No heating coils, so I don't think I'm leaching copper from anything. Might have metal in the water still though. I asked the guy at the store if he had any sequestrant and he didn't know where it was. I should have looked for it myself but didn't as I was in a hurry and didn't know if I needed it. I'll read that link Tim posted now.

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So reading that link makes it look like metal issues. How do I read pH with high chlorine? And heck, I'm kicking myself for thinking of sequestrant but not buying any.

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And I use sequesterant to resolve iron issues as well? This is so stressful... Everything has been fine for months, then 24 hours before listing.

If it is resolved (or at least brought into check) by sequestrant, how long will it take?

I can't drain and refill overnight as I have no way to pump the water out without flooding the yard and it'll take roughly 96 hours to do a half fill I think.

And last question, I think, about sequestrant. The post that Tim linked above mentions several different types for different types of pool (new plaster vs salt water vs regular). Does it really matter? I do know that my salt content is high, higher than a salt water pool as I can actually taste it, so I'm thinking that maybe I should try to get Jack's Magic Purple Stuff if it is available. The pool store opens at 9. The MLS (the house posting) is supposed to go live around 10 AM, people may actually want to come see it within a few hours of that. Wonder if I can get it blue... The wife has said she doesn't want to wait for the pool to be blue before listing since Thursday and Friday are the best days to list so people can come and look on the weekend.

Someone mentioned something about a water table and hoping it was low so I could do a 60% drain. I'm not sure what the water table typically is, but we've had MASSIVE amounts of rainfall in the last couple of weeks. That has probably raised it above normal levels.

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Duraleigh to the rescue!!! :) That makes much more sense.

Yes, sequestrant for iron. It should work fairly quickly, so if you get it in first thing in the morning, you should see a significant improvement before the first prospective buyer arrives. But be aware that it breaks down over time, so you need to replenish regularly.

You might also see if your pool store has sodium thiosulfate for reducing your chlorine levels. Getting the chlorine down may help keep the green from returning immediately. I don't know if it would reduce what green is already there.

Beyond that, I have no knowledge other than what I've read on this site (especially on the link that Tim posted above), so I'll bow out and let the real experts chime in.
 
TomBorg said:
Duraleigh to the rescue!!! :) That makes much more sense.

Yes, sequestrant for iron. It should work fairly quickly, so if you get it in first thing in the morning, you should see a significant improvement before the first prospective buyer arrives. But be aware that it breaks down over time, so you need to replenish regularly. .
Click to expand...

Love confirmation posts! I'm stoked and hopeful that this won't be a disaster now. I think you posted while I was editing my previous post. Thanks for the suggestion on the sodium thiosulfate, I'll see if they have some.
 
According to an old post by chem geek, hydrogen peroxide is a stronger oxidizer than chlorine, and neutralizes chlorine by oxidizing it. Since peroxide is such a strong oxidizer, I would worry that adding peroxide might actually make the green-water problem worse. But that's just a poorly educated guess.
 
Hydrogen peroxide is not a stronger oxidizer than chlorine. Hydrogen peroxide is both an oxidizer and a reducing agent. It is the latter property of it that has the chlorine oxidize the hydrogen peroxide to oxygen gas and conversely the hydrogen peroxide reduce the chlorine to chloride salt.

If the pool has blue plaster then yellow color from iron in the water against a blue background will look green. The high pH from adding a lot of a hypochlorite source of chlorine will precipitate metals in the water and is the likely cause of the colored water. This is why we say to lower the pH of the pool before a SLAM (also the higher pH can cause cloudiness or scaling if the water is already saturated with calcium carbonate). Lowering the chlorine level should lower the pH and may help to clear up the water.
 
Thank you for the correction! I should know better than to reference a thread from 7 years ago. :)

So perhaps the sodium thiosulfate should be the first thing to use, and if that doesn't clear up the green, retest your pH and get it down around 7.2. And if that doesn't clear up the green, try the sequestrant. The sequestrant will probably be the most expensive option anyway.
 
^just to add that the reason you want to get the FC down to 1-2 ppm is because the metal sequestrants WORK right at their respective recommended levels.
And I wouldn't consider the Jacks Magic or Metal Magic "optional" -- that metal has now been liberated and will stain if not sequestered.

If you don't want to lower your ph to 7.2, Metal Magic works and prefers a ph of 7.6, just so you know. But buy whatever they have on hand, and follow the instructions for best results. Don't be surprised if it takes a little more than a regular startup dose to work...but it will work!

Best wishes for a clear (blue) pool and a quick sale ;)
 
I skipped out of work just before the pool store opened and bought 9 lbs of sodium sulfite and 2 bottles of Jack's Magic Pink Stuff. The Pink Stuff is for salt water pools, but I have an abnormally high TDS, or it was at the end of last season. The back of the bottle suggested that the Pink Stuff helped with high TDS and not necessarily that it was for "Salt Water" Pools. So, that's what I got.

Last night, I measured my CYA to be near 5 ppm. The cylinder doesn't go that high, so I had to guess. I added enough liquid CYA add about 25ppm to my pool. I just measured CYA to be just a smidge below 30ppm, so that's great! What is also great is that the pool is no longer emerald green but only a slight tinge of green.

I added about 4.5 lbs of the sodium sulfite to the pool. In about 15 minutes, I'll remeasure chlorine to see where it is. I'm going to go brush to help get it mixed up.

Edit: The house is officially on the market as of 30 minutes ago.

Edit 2: The sodium sulfite bottle said 2.25 lbs will remove 10ppm chlorine in a 15,000 gallon pool. My chlorine measured at 29.5ppm before I added the sodium sulfite. I added 1.5 bottles.

1 bottle is 3 lbs, so 4.5 lbs was added. 10ppm / 2.25 lbs = 4.44 ppm/lb. 4.44ppm/lb * 4.5 lbs = 20 ppm. I should be near 10ppm, but its measuring as 0.

Chem Geek stated the ratio is 2.4 ounces weight of sodium sulfite for 1ppm in 10,000 gallons. This would be 2.4 ounces for 0.66ppm for a 15,000 gallon pool. 4.5 lbs is 72 ounces which should be 0.66ppm / 2.4 oz = 0.275 ppm/oz. 0.275 ppm/oz * 72 oz = 19.8 ppm. Pretty dang close to what the bottle said.

Where the is my other 10ppm chlorine? I'll go test again. Need to check my pH again too.

Edit 3:Was at 0ppm chlorine reading, didn't want to keep it there so I eyeballed half a bottle of 10% liquid chlorine. Got me up to 9ppm, higher than I wanted, but I didn't wait for the water to circulate well so I'm not sure that it was really that high. In any case, I had to get out of there and get back to work. I added 48 oz of The Pink Stuff sequestrant and headed back into work. When I left, the had just a very slight green hue to it. I think this is working. Hope it isn't rainbow colored when I get home this evening!

The pH was also down to about 7.2.
 

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