green cloudy pool water... HELP

[lbridges]

We agree a good set of test numbers is the only really valid starting place.

You seen to be a very rare sort, one with both a vested interest (the company link) as well as a willingness to help for free on a forum - so ask yourself - do you believe the pool store number of 93? It could easily be much higher depending on the test they are employing (I'm assuming turbidity). My personal test, and the one at my local pool store, has no numbers between 90 and 100, so 93???

The OP states the pool was shocked and 4 pounds of stabilized chlorine was added to reach an FC level of 7.5. With a CYA value of 93, the pool likely had insufficient FC before the lawn fertilization. And given the inaccuracies of the CYA test it could be easily be higher.

The fertilization might have tipped the scales toward algae given a too low FC level for the amount of CYA, but IMO something like Phosfree isn't going to fix it, and as far as I know there is no fix for nitrates other than drain and refill. And to fix the algae problem with such a high CYA value will take probably 50+ gallons of 6% bleach (corresponding number of liquid chlorine).

So ultimately I recommended following the advice at the link I posted as it was written a lot better than anything I could manage.

[floridapooltech]

We agree a good set of test numbers is the only really valid starting place.

You seen to be a very rare sort, one with both a vested interest (the company link) as well as a willingness to help for free on a forum - so ask yourself - do you believe the pool store number of 93? It could easily be much higher depending on the test they are employing (I'm assuming turbidity). My personal test, and the one at my local pool store, has no numbers between 90 and 100, so 93???

The OP states the pool was shocked and 4 pounds of stabilized chlorine was added to reach an FC level of 7.5. With a CYA value of 93, the pool likely had insufficient FC before the lawn fertilization. And given the inaccuracies of the CYA test it could be easily be higher.

The fertilization might have tipped the scales toward algae given a too low FC level for the amount of CYA, but IMO something like Phosfree isn't going to fix it, and as far as I know there is no fix for nitrates other than drain and refill. And to fix the algae problem with such a high CYA value will take probably 50+ gallons of 6% bleach (corresponding number of liquid chlorine).

So ultimately I recommended following the advice at the link I posted as it was written a lot better than anything I could manage.

The CYA reading of 93 means they either tested the water using Aquachek test strips have really good eyes and guessed at the color "in between" the 50 and 100, or used a micrometer to get the value of 93 (ok, not a funny joke). It would be a good ideal they take the test again to make sure they receive a positive result.

We are on here to help the community solve problems. A lot of pool owners that visit this forum know who we are, so in most cases, we are just answering their questions before they have the need to call one of our tech's. We aren't a chain store looking only to make a dollar and that's what makes us unique. We don't EVER push anyone to buy something they wouldn't need. We are trained to deal with nitrates & phosphates, and do not sell Natural Chemistry because it is inferior compared to SeaKlear or our PROtech blend (chain stores carry Natural Chemistry to gain several sales of it before the issue is finally fixed as it contains phosphates itself...). You are absolutely correct, with all the science, technology, and years fertilizers have been around....wouldn't you think they'd have a chemical or "easy" fix for fertilizer / nitrates? One would have thought so, yet you still have to dump water and replace with fresh. to be honest, with the CYA at 93 and only 4 lbs. of chlorine/shock, it sounds like they are using the typical Dichlor which shouldn't be used as it is high in both CYA and pH. If anything, liquid Chlorine or Calcium Hypochlorite (no CYA or pH jump) should always be used to shock a pool into a desired FC level. Also, you were stating 50+ gallons of 6% bleach...that's household bleach. Isn't your local pool store selling 12-15% chlorine at a decent price in your area? I can't believe it's less costly to use a bleach half as concentrated to equal the same amount?

Here's the option:

lbridges thinks it's CYA (I think), I think it's Nitrates (like he said everyone has an opinion). It may be a good ideal to compare these two options.

1. 50+ gallons of household bleach (if that's the fix) would cost what? $50 on average?? Would it be more cost effective to dump that in the pool, IF it actually is CYA to match the corresponding levels then let both slide back to a normal level, taking a chance that this may not fix your issue.

OR

2. Drain a good amount of water, then replacing with fresh, which will not only solve a possible CYA overdose, however solve the Nitrate problem if there is one at the same time. A little tip....if you call the city before filling your pool and tell them it's for filling your pool, they give you a huge discount on your water bill for the amount you tell them (not being wasted and no sewage fees).

[lbridges]

Earlier I suggested a drain and refill, so I second option #2 - on that we have firm agreement.

I only spoke to the estimate of 50 gallons of bleach, to be used over some number of days, to give the OP an idea of what they would face if they didn't/couldn't do a drain & refill.

And in my area you still pay full price for water, but they don't charge sewer, so it ends up being half price (in terms of the actual bill you pay), most definitely worth a call to city hall (or whomever).

[floridapooltech]

#2 is definitely the better option than continuing with the chemical cocktails the local store seems to find profitable. Hope this helps (and quickly)! only a month or so of swimming left

[Connie346]

OK, to clarify, 32oz Poolife phosphate remover and 32 oz SeaKlear Phosphate remover were added to the pool on 2 different days once last week and once this week. Also 4# stabilized chlorinate granules (sodium dichlor) were added last week. In addition we added 4 gal of 12.5% chlorine on 2 or 3 different occasions. No improvement.

However, today after adding a total of 15 gal of 12.5% chlorine in a 24 hr. period we are seeing an improvement....water has a blue hue, green seems to be more toward center/bottom drain.....we are excited to see this as it has been 2 1/2 weeks since it has looked this good ( and it doesn't look good yet, but I am encouraged). What to do next???? pH looks good at around 7.8 (may still be high due to shock), OTO test shows burnt orange color (still waiting for my Taylor kit)....we don't want to step back now since we see impovement. Should we add the 6-8" of replacement water now, (it is well water, which may contain iron/NOT city water)?? Should we add more chlorine tonight to be sure it stays high (sunny and 80 here today)??? Or do we just continue to filter and let the existing chlorine level work??? I appreciate all the posts, and am taking all opinions into account.....please advise if you can......thanks!!

[floridapooltech]

OK, to clarify, 32oz Poolife phosphate remover and 32 oz SeaKlear Phosphate remover were added to the pool on 2 different days once last week and once this week. Also 4# stabilized chlorinate granules (sodium dichlor) were added last week. In addition we added 4 gal of 12.5% chlorine on 2 or 3 different occasions. No improvement.

However, today after adding a total of 15 gal of 12.5% chlorine in a 24 hr. period we are seeing an improvement....water has a blue hue, green seems to be more toward center/bottom drain.....we are excited to see this as it has been 2 1/2 weeks since it has looked this good ( and it doesn't look good yet, but I am encouraged). What to do next???? pH looks good at around 7.8 (may still be high due to shock), OTO test shows burnt orange color (still waiting for my Taylor kit)....we don't want to step back now since we see impovement. Should we add the 6-8" of replacement water now, (it is well water, which may contain iron/NOT city water)?? Should we add more chlorine tonight to be sure it stays high (sunny and 80 here today)??? Or do we just continue to filter and let the existing chlorine level work??? I appreciate all the posts, and am taking all opinions into account.....please advise if you can......thanks!!

you were stating before you had a "93" CYA, we'll call this 95 just because like ibridges said, it's impossible to know the in-between number other than halfway between 90-100. You keep adding "stabilized" granular. "stabilized" is just another way of saying "conditioner" or CYA. Adding more of that in your pool is only raising your CYA which is why you have the need for such high FC levels to effectively kill algae. I would recommend since you arent going to drain and replace, to only use your liquid chlorine until your FC is met with the CYA levels. also, a 7.8 pH is on the border for being too high. you don't want this as you will start destroying the pool surface and equipment as well as start affecting the alkalinity levels. This needs to be brought down with some muriatic acid or whatever form you have (sulfuric, pH down, etc...). Every time you add liquid chlorine or bleach, you are raising your pH levels, so this needs to be done at the same time, every time. Make sure when you have your effective FC levels, that you are holding them there until the algae is COMPLETELY dead, or all the money you have just spent will be wasted and you'll start over again. Yes, you should add the replacement water as you will be dilluting the issue some, however, you will need to chlorinate that immediately since it will also dilute the chlorine levels.

Until the algae problem is fixed, you should quit putting more phosphate remover in your pool as you should be working on killing the problem you have rather than preventing it later (it's just pouring money down the drain...or pool however you look at it).

Also, make sure you are running your filter system the whole time until this problem clears up. Sanitation is always #2 after filtration!

[lbridges]

Considering we were disagreeing about the subject before, I should say I agree with everything in the above post.

[chem geek]

Every time you add liquid chlorine or bleach, you are raising your pH levels, so this needs to be done at the same time, every time.

I also agree with what was written though the above needs some clarification. Though it is true that adding a hypochlorite source of chlorine (bleach, chlorinating liquid, Cal-Hypo, lithium hypochlorite) will raise the pH upon addition, the pH will drop as the chlorine gets used up since this is an acidic process. You end up close to where you started except for the small amount of excess lye in bleach and chlorinating liquid (some brands have more excess lye than others). So while I would normally recommend lowering the pH down to around 7.2 before shocking with a hypochlorite source of chlorine, ongoing use of chlorine should not require very much acid addition (I only add acid once every month or two and use 12.5% chlorinating liquid at an average rate of around 1 ppm FC per day). If the pH is seen to rise too much over time, then this is most likely due to the Total Alkalinity (TA) being too high since that increases the rate of outgassing of carbon dioxide which raises the pH (essentially, carbonic acid is removed from the water).

[danneva]

Green algae is a common swimming pool problem, which may appear as a greenish growth on the floor and walls of a swimming pool, a green tint to the pool water, or greenish material suspended in the pool water. The only swimming pool chemical that will kill an algae growth is chlorine based swimming pool is “shock”. But algae reoccurrences happen in a swimming pool because the algae were not completely eradicated when treated. Sometimes poor or misdirected pool water circulation can prevent the pool chemicals from removing all of the algae. When treating a swim pool for algae, it is important that all parts of the pool receive a dose of algaecide. Some of the many types of algae can exist outside the pool and will reinfest the water when brought back in contact with the water. You must also use the recommended dosage of algaecide called for by the manufacturer or risk not killing all the algae even though you do not see any. It is recommended that you follow up with a maintenance dosage of algaecide to keep the algae from reappearing. It is important to note that the algaecide used to kill existing algae may not be the same algaecide you use for preventative maintenance. Another major cause of reoccurring algae, especially if it keeps appearing in the same places, is poor circulation. When treating for existing algae, run your system for 24 hours a day until completely gone. Another way to increase the area of circulation is to run your automatic cleaner. Even when the pool is not dirty, it helps to bring clean, chemically treated water to all nooks and crannies of your pool. Swimmers do a great job of moving water around your pool, too.

[chem geek]

The only swimming pool chemical that will kill an algae growth is chlorine based swimming pool “shock”. But algae reoccurrences happen in a swimming pool because the algae were not completely eradicated when treated.

"Shock" is a verb, not a noun. There is no such thing as chlorine "shock" in spite of that name being added to chlorine products. Chlorine is chlorine -- they are the same ingredients in "shock" as in regular chlorine products. One can prevent algae in a pool by simply maintaining an appropriate Free Chlorine (FC) level relative to the Cyanuric Acid (CYA) level, roughly an FC that is at least 7.5% of the CYA level in manually dosed pools (around 5% in SWG pools).

[Connie346]

Thank you all for the help! To update: (from my own Taylor kit): FC now 22 (yesterday 35), CC 1, TC 23, pH 7.4, CYA 70-75. MY pool water is no longer green at all, cloudy/milky blue...it's trying to clear. I am seeing improvement over the last 48 hours. Still running filter 24/7 x 3 weeks now, without swimming
We have vac/backflushed pool nightly x 3, clarity is improving, though we still cannot see vac head on bottom yet. There has been what looks like brown stuff near the center/bottom drain which comes up easily with the vac. I am hopeful tomorrow we will see the bottom. What to do next....do I want to add an algaecide?? From your calculations I feel I need a fC of around 6...is this so, is the water safe for swimmers at this level?? What about 3" tabs...save them for next year and use only liquid?? I am close to Chicago and we only have 1 month left of swimming season....any advice would be appreciated!! Thanks again!!

[floridapooltech]

Thank you all for the help! To update: (from my own Taylor kit): FC now 22 (yesterday 35), CC 1, TC 23, pH 7.4, CYA 70-75. MY pool water is no longer green at all, cloudy/milky blue...it's trying to clear. I am seeing improvement over the last 48 hours. Still running filter 24/7 x 3 weeks now, without swimming
We have vac/backflushed pool nightly x 3, clarity is improving, though we still cannot see vac head on bottom yet. There has been what looks like brown stuff near the center/bottom drain which comes up easily with the vac. I am hopeful tomorrow we will see the bottom. What to do next....do I want to add an algaecide?? From your calculations I feel I need a fC of around 6...is this so, is the water safe for swimmers at this level?? What about 3" tabs...save them for next year and use only liquid?? I am close to Chicago and we only have 1 month left of swimming season....any advice would be appreciated!! Thanks again!!

Once the problem clears up, you should work on getting that CYA and FC level down to 30-50ppm and 3ppm respectively. If you were to swim at a FC level of 22 right now, you will end up bleaching out your swim wear/toys, etc... If you are trying to make a quick temporary fix to the clarity, you may want to look into using a clarifier or flocculent to speed the process up. (still recommend lowering those FC levels before entering). You may also want to completely take your D.E. filter apart and cleaning all the spent D.E. after this is all said and done to prevent contaminants from re-entering your swimming pool (backwashing only removes 90% of spent D.E.). You mentioned the word "safe" regarding your FC levels...if you mean safe as in will it harm you, likely not, however, you may feel a little burn as this is an extremely high level of chlorine! Hopefully this clears up quite quickly so you may enjoy your swimming pool for the last month of the season!

[Connie346]

Thanks for your advice...what about algaecide use?? Is is necessary? Also, we have a 200# sand filter with new sand as of 2-3 weeks ago, is this ok?

[floridapooltech]

Thanks for your advice...what about algaecide use?? Is is necessary? Also, we have a 200# sand filter with new sand as of 2-3 weeks ago, is this ok?

I don't think you will need an algaecide, you said the only issue at the moment was cloudy water, right? Also, disregard needing to backwash as a sand filter works better the dirtier they are. You may want to try a little "trick" of adding once scoop of D.E. powder into the skimmer while the pump is running as this added D.E. will actually filter even smaller contaminants then plain sand would. Replacement of the sand is NOT necessary as it's too expensive to waste after a few weeks like that, and Sand in a sand filter is good for about 5 years!