Over nite chlorine loss test failed me

[stev32k]

I've been fighting a cloudy pool for a month. One day it was clear as clean glass the next it was turbid. The first thing I did was run an over night chlorine loss test. The result was 0 chlorine loss between 9 PM and 5 AM. I took the valve off the top[ of the filter and used a water hose to clean the sand and it was incredibility, filthy dirty. I spent over 4 hours cleaning the filter and thought I had cured the problem. After a week the pool was still not clear it was better, but not like it had been. I ran another over night chlorine loss test and again there was no chlorine loss. To make a long story short I just about re-built the filter, added a valve to control the flow rate, ran two more over night loss tests (one lost 0.5 ppm and one lost 1.0 ppm), and still the pool would not clear up after almost three weeks.

Finally out of desperation I decided to shock the pool - loss test or no loss test. At 12:45 yesterday I added enough chlorine to bring the level up to mustard shock level, but went over the target of 24 ppm to 29 ppm. At 1:45 the FC was 23.5 a loss of 5.5 ppm. Since that time I have tested hourly except at night and the chlorine consumption has been between 1.5 and 4.0 ppm/hr and is still being used up at that rate. It's now been 33 hours and almost 30 gallons of Clorox later and the chlorine is still being consumed at 1.5 to 3.0 ppm/hr (good thing I just received more testing chemicals).

I'm not sure what to make of all this - the over night chlorine loss not showing a loss, now the pool is consuming chlorine like crazy and the bottom of the pool is loaded with a white powdery looking particulate that comes up in clouds when ever I brush. The O/N loss tests were ran when the FC was in the 4 - 6 ppm range could that have anything to do with the negative results? The only bathers in the pool have been the wife and I and that is not very often.

Is there anything else I should be doing besides keeping the chlorine level up, brushing the pool, and waiting it out?

 

[257WbyMag]

Can you give us a full set of test results?

 

[stev32k]

On the 22nd before starting to shock the results were:
FC 4.0
CC 0
pH 7.5
TA 70
CYA 40

 

[Butterfly]

Do you have good circulation in the deep end?

Do you think the FC could have dipped too low on occassion?

Did you run your pump/filter during the OCLT?

You are doing all the right things, just hold shock until the three criteria are met
See red lines in my sig. I know you know them, but consider it a refresher

 

[stev32k]

Do you have good circulation in the deep end?

I believe I do have good circulation. I pull suction from the bottom drain and the skimmer and any leaves that get in the deep end collect around the drain.

Do you think the FC could have dipped too low on occassion?

That's always possible, but I keep very close check on the pool chemistry. Chlorine and pH are checked daily and other parameters at least weekly.

Did you run your pump/filter during the OCLT?

Yes.

 

[Butterfly]

Well, sounds like a nascent algae bloom - and a mean one. You couldn't see it, but it was eating.
The white stuff that clouds when brushed sounds like dead algae.

Try to keep the dead stuff vac'd out.

Keep shocking, brushing, vac'ing, & backwashing.

Let us know how it goes.

 

[Richard320]

[center:2m12vkng]This organization does not tolerate failure.

[attachment=0:2m12vkng]dr-evil.jpg[/attachment:2m12vkng]You're not done shocking, that's all.
This is war. You can't let up until all the algae is killed.[/center:2m12vkng]

 

[stev32k]

Not much improvement today over yesterday. The bottom drain is visible, but just barely. Chlorine consumption has slowed down compared to yesterday, but still eating up about 0.5 - 1 ppm/hr. There is lots of very fine white material on the bottom. When brushed it comes up like smoke or a cloud. The filter has been in continuous operation for over 48 hours and has been back washed twice. The back wash did not look bad either time - maybe a small amount of the white stuff came out, but no dirty brown looking water.

The overnight chlorine loss last night was 5.0 ppm.

Log
8:30 PM 7/23, FC=28.5, CC=0.5
5:50 AM 7/24, FC=23.5, CC=0.5
7:00 AM vacuum pool, back wash - lots of white powdery like material on bottom, small amount of dead algae looking brown stuff in a couple of spots
9:15 AM, FC=21.5, CC=0.5 - added 182 oz chlorox
10:15 AM, FC=24.5, CC=0.5
12:00 noon, FC=21.5, CC=1.0 - added 182 oz chlorox (heavy rain - real heavy)

Comments or suggestions are welcome - I'm off to Sam's Club for 10 more cases of chloxox.

 

[stev32k]

I started shocking the pool on July 21. Since that time I have added 40 - 1.4 gal jugs of 6% chlorine that's 56 gallons. The over night chlorine loss last night was 5 ppm and the pool is still cloudy, and there are two dinner plate sized pockets of what I assume to be dead algae that collected over night.

The filter has run continuously for six days and the pool is still consuming 0.5 - 1.5 ppm/hr of chlorine. For the first four days there is a very fine, white particulate material generated that collected in large patches on the bottom. The white stuff has gone away and now I seem to be getting more of the dirty brown looking stuff that I assume is dead algae.

In the thirteen years we have had the pool I've never encountered anything like this level of difficulty in getting the water to clear up. I guess I'm looking for assurance that I'm still on the right track and doing everything I should be to clear up the water.

 

[stev32k]

Bama Rambler wrote:
It sounds like you are. How often are you testing and adding chlorine?
What is your CYA level?
What FC are you shocking at?


I'm testing every hour or two and adding chlorine as needed to keep about 24 ppm FC. The CYA when I started was 40 and 24 ppm chlorine is the mustard algae shock level. It just seems that 6 days and 56 gallons of chlorine is a lot if not excessive.

 

[stev32k]

It's not uncommon for it to take a week or more to properly shock if it's bad.
Are you fairly certain it was mustard algae? Because if it wasn't then holding a higher shock level would mean you lose more to the sun but it should also make the process go a little faster.

We used about 50 gallons of bleach to clear my sis' pool and it's about half the size of yours. So I don't think you're that far off.


OK, thanks for the reassurance. I really have no idea if it is mustard algae or something else, but I want to make sure I kill off what ever it is. Guess I'll just keep on doing what I'm doing.

 

[stev32k]

PostPosted: July 27th, 2011, 11:43 am

Joined: March 29th, 2009, 7:47 am
Posts: 200
Location: Mobile, Alabama
Bama Rambler wrote:
Have you ran the OCLT yet?


Yesterday there was a loss of 5 ppm between 8:30 PM and 5 AM. Today the loss was 6 ppm from 8:30 to 5 AM.

 

[stev32k]

After eight days, 65 gallons of 6% bleach, $50 worth of testing chemicals, new filter internals, new multiport valve, and sand I think I finally killed off all the algae. I've had two days of 0 over night chlorine loss and no CC. The water is beginning to clear up and look more like a swimming pool again. It's not crystal clear yet but it is improving. I added 3 cups of DE to help out (the pressure did not go up at all).

What I don't understand is why I had the problem. The pool has been crystal clear for two years and I keep a close check on the chemical levels. There was one incident about a year ago when I was out of town and the wife didn't add chlorine for a couple of days and the water clouded up. The problem was quickly taken care with just one extra jug of chlorine. Other than that I don't believe any of the chemical parameters have been out of range for even one day.

I've beginning to think that I should be shocking the pool on some routine basis - maybe once a month for 24 hours.

 

[Bama Rambler]

Has there been any fertilizing going on near you? (In your yard, neighbors yard, crop dusting, etc) That would explain your sudden issue.

 

[stev32k]

Has there been any fertilizing going on near you? (In your yard, neighbors yard, crop dusting, etc) That would explain your sudden issue.

I put out fertilizer in May nothing since then. I was careful not to get any in the pool, but I guess some could have slipped by. I can't seem to avoid getting grass in the pool when I mow, but that has always happened. The only other unusual event is the amount and number of bugs, snakes, turtles, frogs, lizards, and even a possum getting in the pool this year. Ants have been especially bad. Came out one morning and found four ducks swimming around.

What is strange to me is how fast the pool turned cloudy. It literally happened overnight. One evening the pool crystal clear the next morning the bottom drain was barely visible. There were no signs of algae on the sides or bottom and the chemical levels were in range. I really thought if algae were the cause the FC would go to zero or be very low, but it was in range (4 - 7).

 

[hawkeye]

do yourself a favor go to pool store and get 12.5% chlorine,you will like using it much better

keep that pump running 24\7,seems like you might want to add a little more cya bring it up to 50ppm

you are almost there!! add bleach to pool every night and make sure it isnt getting to low during to day when this is critical. you will get cloudy water, alge blooms without it or worse...

minimum fc level is 4 ppm

 

[yeggim]

I added 3 cups of DE to help out (the pressure did not go up at all).

That's odd. Even though there can be a delay in pressure rise when DE is added to a sand filter, there should be a rise eventually and a steady increase thereafter. Especially if the water is cloudy due to dead algae.