15 replies to this topic

[cda]

We have an above ground pool 24' 15,000 gallons. Opened the pool 2 weeks ago and we haven't been able to swim yet. Was green when we opened it, used shock and algaecide and cleared to a blue color, but couldn't see bottom. When cleaning our cartridge filter, it would look milky. Went to 2-3 pool stores to get tested water in the past 2 weeks and they said our levels were good, but it wouldn't clear. One told us to put saf-t-shock in and run the filter continually, the other told me to put in conditioner and clarifiers. We tried a floc on our own and followed the instructions, actually started the see bottom yesterday but the pool looked green. The chlorine read low or non existent so we shocked it and it immediately turned green worse.....what could it be? I know if I take another sample to the pool place they won't know what to do as usual. Someone mentioned metals in the water....anyone know if that is correct and I should by something for that? HELP...we are having a heat wave close to 100 and the kids can't swim!!!!

[chem geek]

Usually if you shock with a hypochlorite source of chlorine (e.g. chlorinating liquid, bleach, Cal-Hypo, Lithium hypochlorite) then upon addition this raises the pH so if there are metals in the water such as copper then the pool can become more green. So yes, you could have your pool water tested for metals (copper, iron). When the chlorine level drops the pH will also drop so if the green lightens up, then it's very likely you have metals in the water.

However, you should get your own good test kit (for everything except metals) since pool stores do not always reliably measure the water correctly. See this post for a recent example of three wildly different readings from 3 different pool stores measuring the same pool water. You should get a good test kit, either the Taylor K-2006 you can get at a good online price here or the TF100 kit from tftestkits.com here with the latter kit having 36% more volume of reagents so is comparably priced "per test".

It is hard to know if you still have algae growth or not since you did not post water chemistry numbers, especially Free Chlorine (FC) and Cyanuric Acid (CYA), though pH, Combined Chlorine (CC) and Calcium Hardness (CH) would also be helpful. As far as clearing a pool once the algae is killed and the water is just cloudy, an above ground pool has its own issues due to the lack of a floor drain and poor circulation -- usually a flocculant with vacuum to waste helps as it appeared to in your case, but you may have multiple issues with metal as well (or you could have high CYA and by letting the chlorine level drop the algae may be coming back).

Richard

[cda]

I took the water to the pool store and they tested it and the free available chlorine and total available chlorine was a 4 which he said was good The ph was 7.4. After I informed him that upon adding shock to the pool last night it turned really green and this morning it was clear to the bottom, but a lighter green, he said he didn't have to test for metals because he knew it was copper and gave me a bottle of copper algaecide to use. I put it in as directed, in sunlight and 6oz and he said to run the filter for 4 hours. Then he said it was swimmable, we will see. I will keep my fingers crossed. He also said every two weeks to put 2oz in for preventative measure. Kids will be happy if this works, temperature is 103 degrees in the sun today.

[chem geek]

he knew it was copper and gave me a bottle of copper algaecide to use

That doesn't make any sense. Did you mean that he gave you a copper metal sequestrant or remover? Giving you a copper-based algaecide would just add more copper to the pool and make the problem worse. If he gave you a metal sequestrant, then that can remove the copper and would be the right thing to do if indeed there is copper in the pool (which there most likely is). Of course, that begs the question of where the copper came from in the first place. I'll bet a copper-based algaecide was used at some point. It's good to know how the problem occurred so they can be avoided in the future.

[cda]

Good catch...the pool "expert"??? gave me a copper algaecide. I took it back and asked him if this removed copper or added more and he just looked at me. He apologized and gave me Metal free and said to put it in and run the pool for 24 hours. No swimming, check the levels after it runs. Our chlorine was a 0 , the ph was a 7.6, total alkalinity was 170, calcium hardness was a 250, and the total dissolved solids was a 900. They don't test for metals at any pool facility in our area.
I guess it is better to get the information online than in the stores, I don't think they know what they are doing.

[cda]

I put in Metal Free by Natural Chemistry and it looked like the pool was getting better, then I took a chlorine reading the next day and it was 0. Since it was approx 24 hours of running the filter with the additive in it, I added shock to the pool to bring the chlorine up (in the morning) and it turned a lime green again. This is the second day and still no blue pool, a green color. I have slow dissolving tablets in a floater and also added fast dissolving chlorine this morning to try and bring the chlorine reading up, but no luck and still green. Any suggestions? I don't even want to go to another pool store for them to tell me the wrong thing again. I am glad the forum is back up, it was down for awhile.

[chem geek]

Others may have better suggestions, but it sounds to me like not enough Metal Free was used. I assume this product is designed to sequester both iron and especially copper (since that is what it sounds like you have). You want to lower the pH which will put more of the copper back into solution, then use the Metal Free which will bind to it, then slowly raise the pH and/or add more chlorine. Don't shock quickly until the metal problem is handled.

Longer term, water replacement will be needed (you can do partial drain/refill or continuous drain/refill over time) and you'll need to add maintenance doses of Metal Free because it will degrade over time from chlorine. I suspect you got the copper in the pool in the first place from some copper-based algaecide that was used so try and avoid that in the future.

[cda]

Thank you for the advice. We are still unable to swim, pool gets green quickly after adding fast dissolving chlorine tablets in the floater. Our chlorine readings were a 0 at the pool store, and Ph and Alkalinity were in the safe zone. We also tested at home before going to the store and had approx. the same results. We re-treated the pool twice already for the metal. It looks more blue in the morning, however, I noticed when I vacuumed yesterday, it turned green quickly. Do you think that I should vacuum to waste and bypass my cartridge filter because I don't think the particles are being picked up by my filter? I do see some residue each day at the bottom of my pool. We are REALLY frustrated! I think after today, if we don't see some results, it may be time to partially drain and refill, but we are worried about the liner letting go.
Could it be anything else other than metal that turns it green? I have been researching, but don't see any other culprits.
Also, most bottles of chemical don't say what their ingredients are in the product, how would you know what has copper in it or not?
Thanks for your help thus far.

[AlphaChaotic]

Do you think that I should vacuum to waste and bypass my cartridge filter because I don't think the particles are being picked up by my filter?

I definitely recommend vacuuming to waste. After you've killed the algae present in the water, you surely don't want that waste contaminating your filter. Once you've used a floccing agent like "Super Fallout" that algae will fall out of suspension and be ready to vacuumed to waste. Only way that makes sense to do it.

[chem geek]

If you vacuumed and it turned green, that sounds more like something you are churning up from the bottom so I agree that vacuum to waste will get rid of it.

HOWEVER, since your pool isn't holding chlorine, that sounds more like algae -- maybe you've got both a metals problem and algae. For the algae, shock with chlorine and you can lower the pH before you add the chlorine to shock (that will help prevent the metals from turning the pool green and will also help make the chlorine a bit more effective).

You never reported your Cyanuric Acid (CYA) level. If it's really high (> 80) than a partial drain/refill will be needed or you'll have to use something more expensive like a phosphate remover to keep algae from growing. Chlorine alone can prevent and kill algae, but at high CYA levels the level of FC needed becomes impractical.

[cda]

Where do I get a reading of the CYA levels? We are using a standard dropper testing kit for PH and Chlorine and dip sticks Aquachek that tests for ph, free chlorine, total alkalinity, and stabilizer.
A question, if it was algae, wouldn't the pool be cloudy or have some residue on the vinyl liner or steps?
Looks like tomorrow is the draining day, we are fed up; or we may have to call a pool service for assistance.
HAPPY FATHER'S DAY to all the fathers out there.

[chem geek]

Algae initially just consumes chlorine when its nascent and growing, then it turns dull, cloudy, then green. But some algae is more like powder on the bottom or sides. Hard to know in your case -- the green at high pH is indicative of copper but getting green on the bottom that stirs up is unusual -- maybe there's a LOT of copper precipitated.

CYA (Cyanuric Acid) is stabilizer, also called conditioner. So what is that level? Unfortunately, test strips aren't very reliable for that test, but it's better than nothing.

I referred to test kit in this post. If you can't afford those, then Walmart has some inexpensive 5-way or 6-way tests that include CYA. The main downside to the inexpensive tests is that they use a DPD chlorine test that is limited to measuring 5 ppm and bleaches out above 10 ppm. The tests I linked to use a FAS-DPD chlorine test that is accurate to 0.2 ppm and measures up to 50 ppm so is good for measuring chlorine even when shocking.

Richard

[cda]

Went to another pool store that we heard did good water testing and they tested for metal, and guess what, nothing showed up in our water.
They told us to shock the pool with a lithium based shock that is suppose to dissolve quicker and work better. We did that last night and the pool looks blue this morning and the chlorine reading was approx a 2 and the Ph was a little high, about a 7.8. Kids went swimming over the weekend, and no one had green hair or any kind of discomfort due to the water, which was a good thing.

[chem geek]

Went to another pool store that we heard did good water testing and they tested for metal, and guess what, nothing showed up in our water.
They told us to shock the pool with a lithium based shock that is suppose to dissolve quicker and work better. We did that last night and the pool looks blue this morning and the chlorine reading was approx a 2 and the Ph was a little high, about a 7.8. Kids went swimming over the weekend, and no one had green hair or any kind of discomfort due to the water, which was a good thing.

Coincidence. Lithium hypochlorite is the most expensive form of chlorine, but it is identical in its effects to sodium hypochlorite (chlorinating liquid or unscented bleach) assuming you are adding amounts to produce the same Free Chlorine (FC) level. Because Lithium Hypochlorite is somewhat concentrated (usually around 35% available chlorine), you might have added more to raise the FC higher than you did before or the cumulative chlorine you've been adding finally broke down what was apparently algae.

In any event, I'm glad your pool is now clear. You STILL need to get your CYA level determined because if it's high then the algae can come back if you don't maintain a higher FC level. Do you know how much Lithium Hypochlorite powder you added in your 15,000 gallon pool? One pound of Lithium Hypochlorite in your sized pool would raise the FC by 2.8 ppm.

Richard

[cda]

We still can't get a consistent chlorine reading. When testing, everyday, it shows up clear on our test strips or the dropper type test kit. I am adding about 6 fast dissolving chlorine tablets in our floater every day and it goes up a little bit and then later, nothing there. Can someone explain it? We shocked it last night (which we do once a week) and it went green again for awhile and then woke up to a blue pool.

We treated the pool with PhosFree by Natural Chemistry because the pool store mentioned our level may be high. I purchased a Phosphate test kit and it read high (close to 1000ppb). After following instructions, retested recently and it was showing approx 300ppb. I did read about phosphates and it said that it could cause the chlorine problem. I am not sure if it is working though.

I also noticed that the water has a mildewy smell to it. Sounds funny, but the towels and bathing suits have a mildewy smell.

I hope we can get this figured out before the end of the summer. I feel like a chemist when I go out everyday with all these test kits.

[cda]

We still can't get a consistent chlorine reading. When testing, everyday, it shows up clear on our test strips or the dropper type test kit. I am adding about 6 fast dissolving chlorine tablets in our floater every day and it goes up a little bit and then later, nothing there. Can someone explain it? We shocked it last night (which we do once a week) and it went green again for awhile and then woke up to a blue pool.

We treated the pool with PhosFree by Natural Chemistry because the pool store mentioned our level may be high. I purchased a Phosphate test kit and it read high (close to 1000ppb). After following instructions, retested recently and it was showing approx 300ppb. I did read about phosphates and it said that it could cause the chlorine problem. I am not sure if it is working though.

I also noticed that the water has a mildewy smell to it. Sounds funny, but the towels and bathing suits have a mildewy smell.

I hope we can get this figured out before the end of the summer. I feel like a chemist when I go out everyday with all these test kits.