Is this normal / reasonable?

[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.

 

[Bama Rambler]

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

 

[stev32k]

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.

 

[Bama Rambler]

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.

 

[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.

 

[Bama Rambler]

Have you ran the OCLT yet?

 

[stev32k]

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.