Struggling to Keep at Shock Level

Hi, I'm trying to establish the BBB method this year in our AG 16X32 vinyl liner, deep-end-about-15,000-gal pool. I had an algae mess that I've generally cleared up, at least to the naked eye. The water is sparkling but the pool sides still have a green/brown stain that I *think* is fading some.

Other threads I've started have encouraged me to keep it at shock 10 for about a week. I'm having trouble doing that for some reason.

My #'s fluctuate wildly. Last PM I had a 5 FC.

This AM I have a 7 FC after adding a gal of 5.25 bleach last evening. If one gal is supposed to raise the CL 5.25ppm why don't I have a 12 this AM? It didn't rain and there was no sun to dissipate it.

My other #s
CC - 0
TC - 7
pH - 7.1 (I'm having trouble stabilizing this too. Added 4# of 20 Mule 5 days
ago to raise from 6.8 to 7.2. Then went to 7.5 then down now.
Alk - 100
CAL - 130
Cya - 0

Summer'll be half over at this rate before I can ever let the kids in.

Advice please?

CoffeeBean

A gallon of bleach will raise 10,000 gallons of water 5.25ppm. Since your pool is 15,000 gallons that effect is negated some, use Michael's BleachCalc for specific dosages. Also, that chlorine could still be fighting algea, etc in the pool. A real test would be to add bleach tonight then wait an hour, test the Cl and then re-test early AM. Any dip beyond 1-2ppm lets you know that the chlorine is still killing stuff. Also, with 0 CYA you have no stabalizing power in the water so that chlorine is going to get used up and burned up by the sun that much quicker. I would wait to add CYA till you are confident the algea bloom is gone because that will only inhibit the chlorines ability to kill it.

Something has to be using the chlorine and since you lost some overnight, it wasn't the sun so there may still be some algae in there. I would keep the level up at 10 as frequently as you can for a couple more days and see if you start to hold it better.

Also, while the level is below 10, you could let the kids in and shock after they are done.

Here's some threads to look at on high cl levels:

http://www.poolforum.com/pf2/showthread.php?t=1304
http://www.poolforum.com/pf2/showthread.php?t=650

Peter

So, I'm far from an expert here (given this is my first post) but the 5.25% bleach will boost CL 5.25ppm in a 10,000gal pool. Adjusted for 15,000 gal that would be 3.5ppm. That should have landed you around 8.5 but if you're still fighting something it could easily have consumed some of it.

edit - doh, that's what happens when I wait 10 minutes to post - all context gone

Don't know why you're keeping the kids from swimming. With those numbers, I think you should be fine spending all day in the pool.

Thanks all. After I posted I sat and thought about numbers. If 1 gal of bleach adds 5.25ppm to 10K gal and I have 15K (give or take. Even Doughboy can't give me an exact capacity!) then it would take 1.5 gal to get me from a 5 to a 10. It got me where it should've with only a gallon.

I want to turn on the heater because the water's not very warm. Although the days are in the 70's the nights drop down to the low 50s. Without enough CA I can't do that.

How do I increase the CA by using only the BBB method?

Tonight's numbers were:

FC - 9
CC - 0
TC - 9
pH - 7.3? (hard to tell color exactly)
Alk - 100
CA - 160
Cya - 0

I've added 2# of Borax to up the pH and half a gal of bleach tonight. We'll see what it looks like in the AM.

What exactly do color blind people do for pool testing? It's hard for me sometimes to discern the subtle color changes. My son's color blind and couldn't do this to save his soul.

Thanks all.

CoffeeBean

You kinda have a catch 22 going on here...cant' keep Cl up enough to kill algae because of 0 stabilizer, but need stabilizer to maintain Cl levels up. I have about the same size pool...18 x 34 but no deep end. You need stabilizer first off. Get a large size container at home depot/walmart (4lbs.) and pour fill a couple big tube socks, or panty hoses with it and hang in pool. I do mine by return jet and off steps. Then put remaining in skimmer with pump on...and DON'T backwash filter for at least a week. Test for CYA in 5-7 days and you should see your chlorine levels start to balance. Shoot for 30-50 ppm of CYA. As far as the algae on sides, more chlorine and scrubbing is probably all you can do. Too late for algaecide once bloom takes over, but get some polyquat for future proactive needs. Don't worry about any other #'s except cl, pH and CYA for now.

I know Bleach=Cl said not to add cya yet, but I'd go ahead and start getting it into water since it takes a good week to dissolve fully and be readable-- by that time you should have algae killed if you shock properly. You could probably use pucks if you have any since they have CL and stabilizer in them...kill 2 birds with one stone since you need both fast. In the meantime, I'd be in the pool with a scotchbrite pad or something to loosen algae. Most liners are pretty resilient to scrubbing--just go easy and don't use a wire brush!!

Bean,

Your issue is simple and should not be a struggle.....You need chlorine.

Chlorine applied in the daytime will be consumed by the Sun...quite rapidly if you get full Sun...hours, in fact.

Chlorine applied in the evening will be consumed by organics in your pool.....and you still have them.

Until your chlorine is virtually stable overnight.....you need more chlorine!!

Don't be side-tracked by peripheral issues because you will be lulled into thinking your issue is something else....it's not. You must calculate your Chlorine dosage carefully. If your shock value is 10 (it is) you will never get to that point (which you must) if you only add enough to get to 8 or 10....it'll be partially consumed before it ever reaches that level.

Carefully calculate enough chlorine to get your ppm to 12ppm....it will then probably make it to 10ppm (breakpoint) freeing up enough chlorine to make some effective headway on the organics in your pool. (that junk on your sidewalls is organic....brush it often and expose it to the chlorine)

Go swimming!! Get the kids some old swimsuits just in case (unlikely) that you experience a little fading.

You may add CYA now if you like. DO NOT think that will help clear your pool but it will help you retain some chlorine during the day.

Synopsis - You need chlorine :)

Thanks everyone.

This AM my CL is up to 12 and my pH is 7.2 after adding more bleach and borax last PM. Didn't test other things. Running out of reagents. Waiting on Ben's reorder to arrive.

Help me understand this please....I know that sun "uses" up the chlorine but others have said test 2-3 times a day to check that you're staying in "shock" level. If you aren't, the solution would be to add CL but doesn't that fly in the face of the conventional wisdom of adding it at night? If the CL levels fall in one of the daytime tests should you wait til nightfall (or sundown) to add what you need or do it right then?


CBean

While it is true that the sun will consume some chlorine during the day, some chlorine will also be fighting whatever you have in your pool also. By keeping the level up during the day, you will be reinforcing the troops fighting the undesireables so the battle should go faster than if you just wait until night.

Peter

Until you have some cya in the pool, it is necessary to test and add bleach 2 or 3 times a day to stay at shock level. After you add cya and it dissolves, then you'll be able to go to testing and dosing only in the evenings.