Help!! I don't know who to believe - Chlorine Lock?

[btozzo]

Hello All:

It started last week. Took my water to the pool store and was told to add 5 gallons/bags of shock until my chlorine held at 3, and it may take up to 82 gallons. My chlorine was locked. I didn't want to spend the money at that store as they're very expensive and decided to go home.

So, I went home and added 3 gallons of liquid shock right away and and went out to the store. I bought 15 1 pound bags of HTH shock at WalMart. I cam home and dumped in 5 bags and then another 5 3 hours later and still nothing. I had to go to work the next day so I could keep up the three hour thing so I started again when I got home. Still nothing. I had my wife pick up another 10 bags of hth and still nothing. I called NAMCO and asked for a price on liquid shock as I need to buy a lot of it. The guys asked me why and I told him the story. He said that he would absolutely not recommend added 80 gallons/bags of anything to a pool and that I need to try an oxidizer. I got off the phone with him and got a little pissed off and confused and googled "Chlorine Lock" and here I am. I am going to follow pooldoc's process for chlorine demand with a gallon of pool water until I hear back from this post. Could someone please help me out? Here are my vitals:

1. 16x36 inground vinyl
2. CYA 20
3. Free Chlorine 0
4. Total Chlorine 0
5. Ph 7.8
6. Total Alkalinity 218
7. Adjusted Total Alkalinity 212
8. Total Hardness 304

I appreciate it folks. Pretty soon, I'm going to have a drinking habit with this pool,

Bill

[Watermom]

What kind of test kit are you using? Do you have any idea what your cya reading was when you closed the pool last fall?

You don't need anything right now except chlorine -- either bleach or higher concentration liquid chlorine from a pool store. I wouldn't use any more powdered shock. Dichlor will add cya and you are most likely going to need a lot chlorine and you don't want to add a whole lot of cya. Also, no cal-hypo. Your hardness reading is already pretty high. Stick with bleach or liquid chlorine.

We have had several people on the forum this year who have had the same type of situation you have --- excessively high chlorine demand. Although it will probably be frustrating and it may take awhile, it will get straightened out.

If you don't already have one, you need a good test kit. We typically recommend the Taylor K-2006 but for you, I'm going to recommend the K-2006C because it comes with larger bottles of reagents. Since you will be testing frequently, you'll need them. A good price can be found here:

http://www.amatoind.com/k2006c-taylor-test-p-263.html

You need to test as often per day as you possibly can, and each time add enough bleach to take your cl reading back up to 12. The more times per day that you do this, the faster you'll get through this process. There is no such thing as doing it too many times per day. At the very least, do it early morning and also in the evening when the sun is off the pool. When you finally get to where you can hold a chlorine reading overnight with losing no more than 1ppm of chlorine from sundown to sunup, you'll be on the home stretch. It is likely to take a lot of bleach but stick with it and it will work. Read some other threads where people won this battle that they thought would never end.

What is the volume of your pool?

I would also suggest lowering your alk. The process for doing so can be found here:

http://www.poolforum.com/pf2/showthread.php?t=191

Repost with any questions and keep us posted how things are going.

Welcome to the forum. Be prepared for this to take awhile but it WILL work.

[PoolDoc]

As best I can tell, telling a customer who can't keep a chlorine reading in their pool that they have "chlorine lock", is sort of like the doctor who carefully listens to their patient complain of irritated skin, sagely nods, and then states in the most serious voice that the patient has "dermatitis". As a rule, they then neglect to mention that "dermatitis" just means irritated skin!

The only difference is that "dermatitis" always means irritated skin, and "chlorine lock" tends to mean whatever that dealer -- or the dealers in that area -- think it means.

I've seen it applied to high stabilizer / high chlorine pools as in, "Oh, you have algae because your stabilizer is so high that your 'chlorine is locked'.

It's also applied to cases of chlorine that disappears rapidly. It sounds like that's your problem.

I know of three reasons why this can happen:
1. No stabilizer and lots of sun.
2. Use of sodium bromide (Yellow Treat, No-Mor Problems, etc.) and sun.
3. Fall stabilizer converted to spring ammonia.

If your test results are correct, that rules out #1.

You'll have to tell us whether #2 applies.

Usually with #3, you'll still have fairly high combined chlorine.

So . . . we have confusion here.

Oops! Thought of a #4 -- use of chlorine remover OR peroxide as in, Baqua-Shok.

Anyhow, best bet: Add 2 gallons of plain bleach per 10,000 of water in your pool this EVENING, after the sun is well on the way to sunset. Next morning, BEFORE there's much sun, test FC and CC and report the results.

If your problem is #1 or #2, the chlorine will still be there (no sun!). If not, we can at least rule out those two.

Also, report ALL the chemicals used this season AND (if you can) test results at closing last fall AND whatever chemicals you 'closed' with.

PoolDoc

[chem geek]

By the way, the pool store's advice to use an oxidizer is a bit ridiculous since chlorine IS an oxidizer! Using a non-chlorine shock (MPS) is going to be a lot more expensive than using bleach or chlorinating liquid and won't be any better.

You can take a bucket of pool water and add 6% bleach to it. 1/4 teaspoon of 6% bleach in 2 gallons is 10 ppm Free Chlorine (FC). You can then estimate how much chlorine it will take for your pool before it starts to hold. You may decide that's it is better to do a partial drain/refill than just adding chlorine.

Recognize that the DPD chlorine test will bleach out above 10 ppm FC making you think you have no chlorine when you actually have high chlorine. That's why we recommend the Taylor K-2006 that has a FAS-DPD chlorine test that won't bleach out (you at least get a flash of pink and can add more DPD powder) and can measure high chlorine levels accurately.

Though usually the CYA will get to zero when bacteria convert it to ammonia, it doesn't always go completely that way (other nutrients may run out or the bacteria just stop for whatever reason). You can read about my own experience with this and how I fixed it using chlorine alone in this thread (http://www.troublefreepool.com/it-can-happen-to-anyone-zero-chlorine-cya-ammonia-t10974.html).

[waterbear]

One thing I will suggest. Get a cheap OTO test kit (chlorine comparator is shades of yellow) and test your water. If there is truly no chlorine the test will stay colorless. As states above all other forms of testing (Including FAS-DPD and syringaldazine/vanillin used in the majority of test strips) can and will bleach out at very high chlorine levels leading you to believe that there is no chlorine when there actually is. This is just a backup to make sure that there really is no chlorine in the water. If the test turns yellow, orange,m or brown then there is chlorine.
Other then that follow the excellent advice that Ben gave you.

[btozzo]

Wow, thanks for all the help guys!

Alright, as I said I was going to do, I added 1/2 teaspoon of bleach to a gallon of pool water last night at 7:00. This morning at 5:45 my chlorine reading was a little high in the bucket. I have a cheap kit, and am going to buy a Taylor, but it looks like about higher than 3.0 as my kit tops out at 3.o and it was darker than that.

To answer PoolDocs questions:

2. Never heard of those brands and haven't used anything this year other than algaecide, chlorine and pH UP.
3. I think I may have used some stabilizer last year, but I keep bad records. I remember putting in some stuff that the pool store wanted me to that took a long time to dissolve and sat on the botton of the pool. Maybe that was it? But I didn't do it at the end of the season as far as I can remember.
4. Never heard of Baqua Shock.

So what now everyone? Should I just do the calculations and buy the bleach? My pool is 24000 gallons.

Thanks again!

Bill

[CarlD]

You should still post those test numbers. Then explore our forums on testing, maintenance and algae, for starters. There are threads that are stickied, usually authored by either PoolDoc, Watermom, aylad, Poconos, or me.

Then go to PoolDoc's other site, PoolSolutions.com and read the tips that are there. This shouldn't take long and it's interesting reading (except what I wrote...:eek::D--J/K )

But those test numbers will give us a baseline of what to recommend.

We almost always keep it simple, because 99.99% of all pool owner problems ARE, ultimately solved with simple solutions and ordinary chemicals, and very few have to be purchased at a pool store or in the pool section of discount houses.

The best part is it works! Like you, I came here years ago with lots of problems, having been "Pool Stored" to the point where my only other option was to drain and refill my pool. The B-B-B method (Bleach, Borax, and Baking Soda) works on the littlest pools (the one with the problems was a 15' Intex donut--3500 gallons) to the biggest (we now have a 20,000 gallon FantaSea). All you do is adjust amounts you use.

[PoolDoc]

Arg-g-gh! 1/2 tsp in 1 gallon?? You're going to make me work hard. I'm used to figuring doses in 10,000 gallons of water or even 120,000 gallons. But working with 1/2 tsp in 1 gallon? Sheesh.

Ok. Better do it here so someone can check my math.

1 US teaspoon = 4.92892159 milliliters
1 US gallon = 3,785.41178 milliliters or 3,875 gm

1/2 tsp = 2.46 ml = 2.46 gm/H20
at 6% bleach that's approximately 0.148 gm Cl2 equiv

so your dose was
(0.148 / 3 875) * 1 000 000 = 38.1935484

or 38 ppm chlorine.

Yep, if my math and your testing is correct, you've got a lot of chlorine demand there.

I'd recommend using 4 gallon (~10ppm) doses in the evening, and continuing till you hold a residual.

Watch your pH during this, and add borax a box at at time, to keep it above 7.6


Have fun!

PoolDoc

[CarlD]

from Chem_Geek's post:


You can take a bucket of pool water and add 6% bleach to it. 1/4 teaspoon of 6% bleach in 2 gallons is 10 ppm Free Chlorine (FC).

So...1/2 teaspoon in 1 gallon is four times the concentration Chem_Geek lays out.....

I prefer to use a glass eyedropper and add 10ml to 10 liters of water (that's 5 2-liter soda bottles). That's the same as figuring based on 10,000 gallons.....

[btozzo]

Alrighty! Will do!

I have a question though. The way I worked the math was with a proportion. If .5 teaspoons effectively chlorinates 1 gallon of pool water, then 12000 teaspoons should effectively chlorinate 24000 gallons. Converting 12000 teaspoons to gallons gives me 15.625 gallons of bleach. Am I correct? So will I be adding 4 gallons a night for about 4 nights?

Also, Walmart didn;t have Borax! I'm going to have the wife look at Target and Stop n Shop.

Thanks guys,

Bill

[PoolDoc]

So will I be adding 4 gallons a night for about 4 nights?


No, you'll be adding 4 gallons per night, till you can hold a residual. Trying to analytically predict doses like that ends up being a distraction. You might be right -- but you'd still get there just as surely without the prediction.

Or, you might be wrong, and then pause, and come back here asking what to do. That would slow things down for everyone.

Testing and dosing is not so precise -- in the pool biz -- that predictions work especially well. So instead of testing and then dosing . . . . test, then dose, then test and dose so more till you get there. Works every time!

PoolDoc

[CarlD]

The way I worked the math was with a proportion. If .5 teaspoons effectively chlorinates 1 gallon of pool water, then 12000 teaspoons should effectively chlorinate 24000 gallons. Converting 12000 teaspoons to gallons gives me 15.625 gallons of bleach. Am I correct? So will I be adding 4 gallons a night for about 4 nights?

I'm not sure how you go there, but ultimately the calculation is correct.

Here's the formula you need:
(1,000,000/pool size) * concentration of bleach * # gals bleach = FC added

or, in your case, using 6% bleach

(1,000,000/24,000) * 0.06 * 4 gallons=9.99ppm of free chlorine added per night.

But you cannot be sure with that, as Ben says. You must still be testing because chlorine will be consumed.

For a 24,000 gal pool, one gallon of 6% bleach adds 2.5ppm of FC.

[btozzo]

Got it. I was just trying to get a sense of how much this will cost me. I was planning on testing and dosing until I got there and then testing some more!

I'm going to start tonight and I'll be posting my results daily. Thanks so much everyone, I'm seeing some light at the end of my "No Chlorine Tunnel!"

Bill

[chem geek]

If the circulation in your pool is decent, you can initially add 10 ppm FC then wait an hour then retest and add more if the FC is very low or zero. The chlorine gets consumed very quickly at first. You may see some of it register as Combined Chlorine (CC), but it's the Free Chlorine (FC) you want to look at.

The bucket test gives you a rough minimum requirement, but your chlorine demand may still be high for some days after the chlorine at least somewhat holds. You can see this effect in the thread describing my experience of this which I summarized in this post (http://www.troublefreepool.com/it-can-happen-to-anyone-zero-chlorine-cya-ammonia-t10974.html#p88238).

[btozzo]

Hello All!

4 Gallons of bleach in my pool last night and this morning my test tube was nice and YELLOW! Looks like about 3ppm or better. So this is encouraging. I'm going to retest tonight and add more if necessary.

Now, there is a lot of "stuff" at the bottom of my pool. It seems that no matter how much I vacuum it always comes back. The water is clear and when I vacuum it becomes cloudy. My filter "Hayward 265" seems to need backwashing everyday as well. Am I correct in assuming that the organics eat the chlorine, some die and fall to their death on the floor of my pool and end up clogging my filter. The rest are floating around waiting for more chlorine to eat them? I wish I could afford one of those "TigerSharks" to clean the pool as I seem to be spinning my wheels with the vacuum. Could you guys also offer me some advice about my filter/circulation problems? Here are the vitals:

1. Hayward EC265
2. Dismantled and cleaned twice already. Soaked in a garbage pale with a bottle of "StripKwik" to degrease.
3. Backwashed and bumped more times than I can count. I've already gone through about 2 bags of DE.

Thanks again everyone,

Bill

[PoolDoc]

Stuff that chlorine oxidizes is essentially 'gone', so far as filtration and settling goes, unless that stuff is iron and it's not in your case.

Brown stuff at the bottom of the pool is often dead algae, but from what you've said, it doesn't sound like that's happening either.

Gray stuff at the bottom, especially in a clear pool with a DE filter is often . . . DE.

And that means either a leak in your filter (torn 'membrane', missing tube, misplaced connection, cracked header) or an error in your filter startup process.

If there's enough stuff to pinch, grab a pinchful: DE will be a little gritty.

If it is DE, your filter OR your backwash process needs some work.

PoolDoc

[herrmanncr]

I am having the same problem. "Chlorine lock". I googled and it braught me here. Don't mean to jump in but need to know how much bleach to use. Posted #s last night but didn't show.Pool is 21000 ig vinyl.
Off memory think they are
Fc .2
Ph 7
Alk 130
Calc 400
Cya 94
These are pool store #. I need to get a kit.
Any help is appreciated. Water is clear for now. Been shocking with all kinds. Usinf algea 60. No metals present.
Thanks , chris

[aylad]

herrmanncr,

I answered this in your thread. It is helpful if you'll keep your information in that thread that you started, because it gets really confusing for those trying to help two different posters within the same thread. I promise that we're looking at yours as often as we are looking here! It doesn't hurt to read other, similar threads, but please keep your pool details in your own thread to make it easier on us.

Thanks!

Janet

[btozzo]

Hello All!!

Well, I tested again last night and my Chlorine was still above 3.0 and I am thrilled! I can't thank everyone enough. Now I just have to get all the rap off the bottom of my pool. I wish I could rent an electric robotic pool cleaner . . .

Ben, I am going to subscribe to PoolSolutions!! BBB is the Method for ME!!!

Bill

[Watermom]

Ben, I am going to subscribe to PoolSolutions!! BBB is the Method for ME!!!

Bill

Glad to have you!

[Spensar]

Hello All!!

Well, I tested again last night and my Chlorine was still above 3.0 and I am thrilled! I can't thank everyone enough. Now I just have to get all the rap off the bottom of my pool. I wish I could rent an electric robotic pool cleaner . . .

Ben, I am going to subscribe to PoolSolutions!! BBB is the Method for ME!!!

Bill

When I have the light "dust" on the bottom of the pool, dead algae, after a clean-up it doesn't get caught by the sand filter. I let it settle on the bottom, set the filter to waste (or drain) and vaccum it straight down the drain. Takes a bit of water but eliminates the mess.