HELP!

[mobrien719]

Major pool issues and I don't know where to start. I normally maintain pool. I went out of town for 10 days with kids and left husband in charge. Pool looked great prior to leaving. CYA level was over 100 and my husband's job while we were gone was to partially drain pool to bring level down. Prior to doing this, pool became cloudy and murky. He drained about 10 inches and refilled. Then shocked using granules (gasp!) and adding pucks to chlorinator which we hadn't been using. Pool continues to be cloudy. Brown stains have appeared at creases around pool. They do not brush off. We brought water sample into pool store. Here are the readings. (we got very similar test results using our kit).
TC 3.1
Free chlorine 0.2
pH 7.0
total alkalinity 210
calcium hardness 250
stabilizer 25
copper 0.1
phosphate 350

1. How does our cya level go from over 100 to 25? We didn't drain that much water.
2. Where do I even start to get levels back to where they should be? I have no idea what to adjust first.

35 K gallon vinyl liner above ground pool.

Any help is appreciated!

 

[Butterfly]

What test kit are you using?

CYA can disappear from bacteria converting CYA to ammonia. Having higher CC than FC is one indication.

It would be great if you could have another test done, esp for FC, CC & CYA to confirm.

 

[elwood58]

Looks like you have significant CC and need to do the shock process. Using liquid chlorine will also likely bring your pH up some, as it is low. Keep shocking until no CC, clear water, and no overnight loss of FC.

Was the refill from a well? Possible iron in the water?

 

[mobrien719]

Do I need to shock more than once a day? If so, how often? Is the alkalinity a problem? Do we need to add more CYA to the pool? In what order do we adjust levels?
We used city water. Thanks for the help so far!

I did retest using our TF-100 kit.

FC= 3
CC= 4
CYA= 20

 

[duraleigh]

Do I need to shock more than once a day?

read "The ABC's of Pool Water Chemistry" up in Pool School. Then, read "How to Shock Your Pool" here...pool-school/shocking_your_pool.

You will find shocking your pool is a process involving thecontinual application of chlorine....not a one-time dose like you are accustomed to.

And, yes, you clearly need to shock the pool.

Leave CYA alone until you finish the shock process.

 

[Butterfly]

Do I need to shock more than once a day? If so, how often? Is the alkalinity a problem? Do we need to add more CYA to the pool? In what order do we adjust levels?
We used city water. Thanks for the help so far!

I did retest using our TF-100 kit.

FC= 3
CC= 4
CYA= 20

Okay. It is going to take a lot of chlorine to maintain shock for that size pool.
You need to shock as often as once per hour. The more often you can raise to shock level, the faster the process will go. Concentrate on doing most of the shocking when the sun is off the pool. Shock level (for 20 CYA) is 10ppm FC.

I suggest you do not add any more CYA until you are done shocking. Use only bleach/liquid chlorine to shock. Follow shock directions here: pool-school/shocking_your_pool

Anything else that needs to be adjusted can be done after you are done shocking. See red lines in my sig.