Cloudy pool will not clear

[patrickc01]

Hi Everyone,
My wife and I bought a house that included an 8500 gallon above ground pool.
We have tried for the last month to get it ready for swimming, but despite repeated trips to the pool store, are still stuck.
We have added 8lbs of shock, and 4 gallons of liquid shock. Our last testing came out:
TC 0.5
FC 0.5
pH 7.3
TA 105
CH 50
Stabilizer 30

The water has gone from pond green to a very cloudy bluish green color. Visibility is about 1 ft, even though we have had the sand filter going for 2 weeks now. Also, despite all of the shock we have added, the chlorine level has barely risen.
The pool store has advised us to put chlorine tablets in a floater in the pool, but I am not sure this will help clear it up.
I was hoping I could find some good advice here. Should we keep adding chlorine to get the level high enough, or should we use liquid floc to try and precipitate the cloudiness?
If it matters, we dont believe the pool has been used in the last 2-3 years.
Thank you for any advice!

 

[duraleigh]

Welcome to the forum. . Your journey should start with reading "The ABC's of Pool Water Chemistry" up in Pool School. Once that is digested and you are comfortable your pool is operating correctly, you will need to SLAM the pool. That article is in Pool School, also.

Those two articles (along with our help) will get your pool back in tip top shape and you'll be swimming in crystal clear water.

 

[JohnN]

How did you get those test results? Was the pool green before it became blue? Also, you are missing a very important test result, CYA. In order to properly clear the pool, you will need to know that. Based on those numbers, it looks like you probably have an algae outbreak, and will need to SLAM the pool. In order to follow the SLAM process, you will need to get the proper test kit (linked in my signature) and follow the SLAM article to the letter (link also in my signature).

 

[JasonLion]

Do you know your CYA level? CYA makes a huge difference to how the pool behaves. Higher CYA levels mean you need to use more chlorine to get the same effect. If CYA is very high you will have a very difficult time clearing algae out of the pool.

When you have a chance, I recommend doing some reading in Pool School (button near the top right of ever page of this site).

 

[patrickc01]

Thanks, I posted the question, then started reading. I have been getting all of my results from the pool store (they have some type of digital instrument). CYA is not included on the report. I will come back after doing more reading and getting a test kit.
Thanks!

 

[patrickc01]

I received my Taylor FAS-DPD K-2006 test kit today. Read the book and tried my first test.
My readings were:
FC = 0.2
CC = 0.4
pH = 7.6
TA = 120
CH = 60
CYA = 34

From what I understand, my next step is to Slam the pool.
To do this, I should first lower the pH to 7.4-7.5, then add enough chlorine to reach FC 13-14. I will then need to test the FC 2x a day until the water is clear, the OCLT is less than 1.0 and the CC is less than 0.5.
Does this sound right?
Also, since the water is already cloudy, should I expect the CC to rise dramatically when I start the process?
Finally to raise the FC to 13, I should add about 118oz of 12% bleach.
Is there anything else I should be prepared for?
Thanks!

 

[Abigail K]

For SLAM, you should lower your pH to 7.2-7.5.
Test FC and add bleach more often if possible.
There isn't really a pattern to CC levels during SLAM.

I would recommend using a 10ml sample for the FC/CC test, it saves reagents, each drop counts as 0.5ppm and it is precise enough.

 

[patrickc01]

Thanks, I like your idea of using the 10ml sample for FC/CC. I was originally planning on doing it at the large volume.

 

[jblizzle]

Even using 10ml, you likely should order refills for the FAS-DPD test now (may as well get the CYA reagent as well while you are at it) so you do not run out in the middle of the SLAM ... this is one reason I recommend the TF-100 over the K-2006.

You can get refill at tftestkits.net that might be a better deal.

 

[patrickc01]

Last night I started the SLAM.
At 8pm my numbers were:
FC 0.2
CC 0.2
pH 7.3
TA = 120
CH = 60
CYA = 34

I added 164oz of 8.25% Clorox.

This morning I checked the basics and recorded
FC 0.5 (These were done with 10ml water sample)
CC 1.0
pH 7.2

Should the FC and CC risen more over the night? And does this mean I need to add ~160 more oz of Clorox?
I guess I was expecting more a dramatic change.

Thanks

 

[Abigail K]

FC is consumed overnight as you are fighting algae.
CC has no real pattern during SLAM.

Yes, you need to keep testing FC and adding Clorox.
No need to test pH during SLAM.

 

[jmbradwell]

On the initial stages of a SLAM you need to test way more often.

1, Add chlorine to get to SLAM level
2, Wait 30 minutes to an hour (brush while you are waiting)
3, Test again
4, Repeat steps 1,2, and 3

You have to hit it hard in the beginning of a SLAM. Waiting 8 hours gives the algae a chance to recover. I've read that algae can double in quantity in 3 to 8 hours.

Good luck.

 

[Richard320]

You're on the right track. Just as an aside, pictures would be nice. We like swamp pictures.

Early on in the SLAM, you will consume bleach at an alarming rate. But as you kill off more algae, there is less and less to reproduce, so it's one of those exponential things where it drops rapidly and then sort of flatlines. Typically, after a couple days the chlorine demand drops and the pool is just cloudy and you have to wait patiently for the filter to clear it up.

Do not neglect to vacuum and brush, especially in those hiding places inside ladder rails and beneath rungs and behind steps.

Once you hit that wall where the chlorine is holding pretty good but you start agonizing because it isn't clearing, then worry about improving circulation. Point a return down to stir the dead algae carcasses up where the skimmer can grab them. Or hook up the vacuum and set it on its side so you;re drawing water from down low, where the stuff naturally settles.

It's still quite possible that you can have crystal clear sparkling water that will be the envy of all who see it by August!