Water cloudy after hot weather, can't get it to clear up

Causes and cures for cloudy swimming pool water.
Milky pool water, white, pink, brown, purple, black cloudy water.
syarb002
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Water cloudy after hot weather, can't get it to clear up

Postby syarb002 » Fri 10 Jul, 2009 15:21

Problem: Pool was fine for about a month and a half. We had a weekend of 90-95° weather and the water turned cloudy. I've tested and adjusted the pH, chlorine levels, added algaecide (50%), and have been using a clarifier. Also have been running the filter 24/7 and keeping the cartridge clean, as well as vacuuming and skimming the water with no luck. Some of the info below is missing because I do not have a test for all of it.

This is really confusing me, please help if you can!

FC: 0.6 ppm
TC: ?
pH: 7.6
TA: 50-60 ppm
CH: ?
CYA: 35 ppm (not tested--per the dosage instructions on the chemical label)

My pool: Intex 15' x 48" Vinyl, above-ground, ~5000 gal.
Pool chemicals: 3" Chlorine Tablets (floater), Chlorine Shock, Algaecide (20 and 50%), Clarifier, Sodium Bi-carb (pH Up)
My pump & filter: Intex Replaceable Filter Cartridge w/ Automatic Skimmer, 1000 GPH
Other info: Water temp ~70-75°F, not used very frequently, cloudiness seems to worsen with hotter weather


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Swim Today
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Water cloudy after hot weather, can't get it to clear up

Postby Swim Today » Sat 11 Jul, 2009 16:08

Only thing I see at the moment is the TA is low. That should be between 80-120ppm. Try bringing that back up first and see if that helps with the cloudiness. To raise it you add what is called alkalinity balance control every pool store should carry it. With the pool you have and the level your at it will take about 2 lbs to get back to the level you need it at.
syarb002
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Water cloudy after hot weather, can't get it to clear up

Postby syarb002 » Sat 11 Jul, 2009 17:24

Thanks, Swim Today! I ended up taking a sample to a pool place today for a better test. They recommended raising the alkalinity as well, and also adding calcium. The alkalinity stuff has been in the pool for about 6 hours, the calcium I added about 2 hours ago with no noticeable change, yet. Here are the test results the pool place came up with:

FC: 0.38 ppm
TC: 0.47 ppm
pH: 7.22
TA: 27 ppm
CH: 24 ppm
CYA: 33 ppm

I'm beginning to see a few small, hazy spots at the bottom now. When I move the net by them, they dissipate. Is this the clarifier working? Or am I dealing with a different problem altogether?
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Swim Today
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Water cloudy after hot weather, can't get it to clear up

Postby Swim Today » Sat 11 Jul, 2009 17:42

The calcium will take a little while to dissolve into the water. It's one of the toughest things to get to dissolve. The spots may either be undissolved particles but more likely just dead particles from bringing the TA back in line. If they are still there in the morning just vacuum them up and you should be fine. Make sure you keep your filter running as long as possible to keep the water moving and circulating. Also the Intex pool filters clog up fast so you probably will want to clean it a couple times a day till the water gets clear. Also the PH is right at the lowest you want it so it may not be a bad idea to raise that ever so slightly. It may also not be a bad idea to add an algaecide again to the water when everything is back in check.
syarb002
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Water cloudy after hot weather, can't get it to clear up

Postby syarb002 » Sat 11 Jul, 2009 18:28

I'm hoping the spots won't be a huge problem. The pool was never 100% free of a few specks of dirt.

My filter is running 24/7 and I just put in a brand new cartridge this morning. When you say the Intex filters clog up pretty quickly, do you mean the cartridges get dirty really quick, or the actual pump and filter clog up? I can see the top of the pump at the bottom of the filter housing, and it looks fairly clean, but I can't very far into it.

I do have some pH up, and more algaecide that I can add once it clears up. The pool place recommended, also, that I shock it first thing tomorrow morning (roughly 12-16 hours after adjusting TA and CH).
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Water cloudy after hot weather, can't get it to clear up

Postby chem geek » Sat 11 Jul, 2009 18:34

There's no way that a low TA or low CH would have caused cloudiness. Did anyone notice the FC at only 0.38 ppm? If the CYA level is truly 33 ppm, then you would need to have a minimum FC of at least 2.5 ppm at all times or else algae can grow. When most green algae first grows, this first shows up as an unusual chlorine demand, then the water turns dull, then cloudy, and eventually green. I suggest you shock the pool with chlorine as described in the article Defeating Algae .
syarb002
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Water cloudy after hot weather, can't get it to clear up

Postby syarb002 » Sat 11 Jul, 2009 19:05

I just tested again with my own testing kit, and while the Alkalinity seems to be up in the GOOD range, chlorine level has definitely dropped. Water might be a tad clearer than before but it's still cloudy.

Chem Geek, I did find that interesting that the FC looked low by the test report sheet they gave me, but I trusted the "pros" to help me out. They have on here that the FC should be between 0.6 and 1.5, and TC should be no greater than 3.0. Not sure why they didn't recommend raising chlorine level, if for no other reason, just because it was low.

My CYA is pretty good I think, so is algae why I'm losing chlorine? Should I go ahead and shock the crap out of it until it clears? I've been using 1/2lb of shock at a time...
chem geek
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Water cloudy after hot weather, can't get it to clear up

Postby chem geek » Sat 11 Jul, 2009 19:36

syarb002 wrote:My CYA is pretty good I think, so is algae why I'm losing chlorine? Should I go ahead and shock the crap out of it until it clears? I've been using 1/2lb of shock at a time...

YES, algae is why you are losing chlorine! But what is the kind of chlorine you plan on using for shocking? Do not use Dichlor as it will increase CYA. If your CH is still low, you could use Cal-Hypo, but will need to pre-dissolve it in a bucket of water first. The best thing to use would be chlorinating liquid or 6% unscented bleach. You don't just throw some in and wait, but add enough to raise the FC to shock level which is around 13 ppm and you MAINTAIN it, so I would overshoot to 15-18 ppm and add more chlorine when it gets to or below 13. If you hit this hard now, it will be MUCH easier to overcome compared to a full algae bloom which can take a week to clear up (see this post for an example of how a pool was cleared of a lot of algae using bleach alone).

Whenever you add concentrated chemicals to the pool, do so by adding them slowly over a return flow with the pump running in the deep end (if applicable) and then lightly brush the side and bottom of the pool in the area where you added the chemical to ensure thorough mixing.

The pool store is dead wrong about the chlorine levels they are suggesting unless you plan to use a supplemental algaecide or phosphate remover at extra cost. Though you could use algaecide weekly (such as PolyQuat 60), you could also consider using borates. They aren't necessary if you maintain an appropriate FC level for your CYA level, but they are insurance in case you aren't diligent about maintaining the chlorine level. All of this and much, much more is in the Pool School (borates are more advanced so are in the Further Reading section in this article ).
syarb002
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Water cloudy after hot weather, can't get it to clear up

Postby syarb002 » Sat 11 Jul, 2009 20:10

The Pool School page is very useful, thanks for pointing that out. I didn't find that one when I was searching for help online.

Of course, I've got a big box of shock and it says its sodium dichlor. What I also have, are two large jugs of Clorox. They both say sodium hypochlorate 6% on the label. Clorox is also incredibly cheap:) Is there anything wrong with it, if its the regular stuff?

So now, I know my CYA is somewhere in the 30-35 ppm range, my FC is about 0.4 ppm, and I'm going to use bleach to raise the FC up to about 15 ppm and hold it there. The pool calculator says I need to add 151oz. How long do I need to hold the level at 15 ppm before letting it back down?

Thanks a bunch!
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Water cloudy after hot weather, can't get it to clear up

Postby chem geek » Sat 11 Jul, 2009 20:57

Do NOT use the Dichlor. Use the Clorox and get more (or get chlorinating liquid if your pool store or hardware store sells it and it's priced reasonably relative to Clorox accounting for strength). Yes, it's the regular UNSCENTED Clorox bleach that you want. It will say "6% Sodium Hypochlorite" in the ingredients list and will also probably say "5.7% Available Chlorine" because it is actually registered with the EPA for use in pools.

You hold the FC at the high shock level until three things occur: 1) the water becomes clear, 2) you measure a drop of <= 1 ppm FC overnight and 3) you measure <= 0.5 ppm Combined Chlorine (CC).

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