bleach, pool calculator, and one drop at a time...

[slawton]

Regarding Shocking:

I have two questions for which I seek clarity:

1. Why is it that when the pool calculator calls for a certain number of ounces of bleach to get the FC to, say, 30, and I put that much bleach in the pool and then test several hours later, the FC isn't the amount is should be?

Then, I again put the numbers into the calculator, put in the recommended bleach, wait several hours, test and I still have a long way to go.

I don't get why the calculator states a certain amount of bleach will bring the FC 's to a certain level but it doesn't work.

My second question is:

2. Do I really have to go one drop at a time when testing FC for shock levels....?! I mean a potential 60 drops with a swish in between each single drop seems ridiculous. Today, I started going 5 drops and swish, until I began to get closer to the anticipated number and I could see the water beginning to go toward clear.

It that good enough?

 

[Guest]

I'm going to ask a stupid question ( )-when you go to the Pool Calculator, do you check the concentration on the chlorine to see that it corresponds with what you have and are adding? That might be the answer, as there are options and you may have a default concentration selected that is throwing you off. I find it to be very accurate, and I use it daily, so something sounds off.

As for question number 2-you need a SpeedStir! I use several drops at a time if I know where I'm headed, and when I think I'm close, I slow down on the drops. I don't think that makes too much difference, within reason!

 

[woodyp]

How much "difference" are we talking about over a period of several "hours"? Is the pool green or anything visibly growing/why are you shocking?

 

[hayfarmer]

your calculation of your gallons in your pool may be off, OR you may have algae that is using your bleach when you put it in.. have you done an over night test.. test the FC right at dark, and then again in the morning before the sun hits the pool... if it drops more the 1ppm then you have something in the water... Keep shocking until it holds over night...

 

[Txmat]

We are all saying about the same thing, but I will add my two cents. Assuming you have the correct pool capacity and the right concentration of bleach selected then the explanation is in the several hours. When you add the amount of bleach called for by the pool calculator the CL level will indeed rise to the target level, but if you are shocking to kill off some organics the CL will begin it's work. As it kills off organics the FC is used up along with some being burned by the sun depending on your CYA level. So when you test several hours later some of the FC has been used and you will get a lower reading. Next time you add bleach to bring it to shock level, brush to mix it all in and then test within about 30 min and your level should still be very close to the shock level. The longer you wait to test the more FC will have been used.

As to your second question, I do not know and agree it is a pain to stir in between each drop. I bought the speed stir so I did not have to do so much swishing.

 

[slawton]

I have been struggling with this for some time. Yes, I do have visible algae. I just started shocking again today after reading the advice by duraleigh:

"You have visible algae.....you need to shock.

Do not worry over 3-5ppm or 4-6ppm.......that's not where the problem is.

Chlorine kills algae. If you have algae, you should bring your pool to shock level and hold it there until....
1. Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1ppm.

Do not let the chlorine go below shock value until you can satisfy those three criteria. It may take longer than you like, but the problem is inadequate chlorine in your pool will let the algae reestablish itself. At some point, your FC became inadequate and algae got a foothold. Shock the pool according to the article in Pool School and the pool will clear."



See this post when it started: is-it-dead-was-slimebag-sadness-t25493.html

and my lament here: i-simply-want-clear-water-and-a-life-outside-fighting-algae-t26333.html

I started at an FC of 3.2 this last night. The first test after adding the recommended bleach was FC 22. I put this new number into the pool calculator, added the recommended bleach, checked a few hours later and the FC was at 17. I recently added more bleach as I try to get up to about FC = 30.

I am using the 6% bleach that the PC suggests. I do wonder if my gallons might be off some....good point there.

I am going to look into this speedstir thing!

 

[slawton]

I will try the test more soon next time as you suggest Txmat. I have always assumed you needed to wait awhile until the bleach as a chance to fully circulate. My pump is 2,000 gallons per hour and the pool is 8,400 or so gallons.

Another thing I wonder is could the algae come from the solar cover? I never thought of that before now.

 

[Txmat]

You don't have to test sooner except to prove to yourself that the Pool Calculations work. However, if you want to get through the shocking process in the least amount of time - test and bring back to shock level every hour. When you start showing a 1 or 2 point drop in an hour then test and shock every 2 hours and so on. How did you get the 8,400 gal capacity? I inserted your dimensions in the Pool Calculator ( at the bottom) and it comes up with 9,300 gal. I also wonder where you got the shock level of 30? Again according to the Pool Calculator the shock level is 16. The actual amount of bleach that the Pool Calculator will tell you to add to get to your target is based on your CYA. I assume you have entered the correct value.

 

[slawton]

I am going by this chart: http://www.troublefreepool.com/chlorine-cya-chart-t2346.html

I took off 3% based on the info. below the chart about SWG's. It's not exactly 30 but I couldn't recall the exact number when I made the post.

How long do you stay at full FC shock level before you let it start coming down?

Also, I took the gallons from the intex manual for my pool. Maybe that wasn't such a good idea?

 

[duraleigh]

How long do you stay at full FC shock level before you let it start coming down?

1. Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1ppm.

 

[slawton]

How quickly we forget!

And how often should I test to make sure the pool is still at shock level?

I mean, I am going to purchase stock in R-0871...

As far as the gallons, I actually measured the water depth and although the Intex is listed at 52" the water only measured 44" (I do have the water just a tad on the low side of full right now as I have a 7 year old.

That actually calculates to 8,200 gallons on the Pool Calculator, so I should be good there.

 

[Txmat]

I assume the manual is correct on the number of gallons. Thanks for explaining how you arrived at 30 FC for shock. I don't recall if you posted your CYA, but according to the chart 30 would mean your CYA is 80. Is it that high? If so, if it were me I would want to reduce my CYA to 40 and the way I would go about it is to plug the actual number into the Pool Calculator and my target of 40 and see what percentage of water I needed to drain and replace. I had to do that earlier this summer when I used trichlor too long and got my CYA too high.

 

[slawton]

I got my CYA level from this in Pool School, see paragraph 3.


http://www.troublefreepool.com/pool-school/water_balance_saltwater_generator


Also, I you may have missed this explanation of the gallons I posted above:

As far as the gallons, I actually measured the water depth and although the Intex is listed at 52" the water only measured 44" (I do have the water just a tad on the low side of full right now as I have a 7 year old.

That actually calculates to 8,200 gallons on the Pool Calculator, so I should be good there.

52" in this pool would and the water would be right up to the top. 52" looks good on the box though, when you are shopping for it in the store!

 

[Txmat]

Yes, you are close enough on the gallons.

I understand now. I am sure you have actually measured the CYA and it is 80, so you are using it in the shock table.

You are on your way. How is the water looking?

 

[Butterfly]

And how often should I test to make sure the pool is still at shock level?

Shocking:
1. Measure the FC level

2. Add enough chlorine to bring FC up to shock level

3. Repeat steps 1 and 2 as frequently as practical, as often as once per hour, and not less than twice a day, until:
A. CC is 0.5 or lower;

B. An overnight FC loss test shows a loss of 1.0 ppm or less;

C. And, if you don't have a FAS-DPD test kit, the water is clear.

There is a lot of info to absorb. You are doing a great job.

What size/type filter do you have? Sorry if I missed it.

 

[slawton]

Txmat,

Yes, I do indeed measure the CYA using the TF-100 test kit.

Regarding how the water looks, after the second round of shock I saw a lot of algae on the bottom of the pool. I brushed it to get it into the water and hopefully through the filter.

Since, the water doesn't have that green color anymore but it is just quite cloudy.

I have continued testing throughout day and now the FC is not losing much each time.

Butterfly,

Where I know I have been missing the boat is in number 3. I haven't kept this up until the water is clear.

And what is a FAS-DPT test kit and how would that help?

I have the TF-100.

Thanks for all the advice here. I am determined to lick this thing and hopefully learn much in the process. I really want to avoid the pool stores! I broke down at Walmart yesterday and purchased some extra strength algaecide but I decided not to use it. I really want to stick to the BBB plan. Call me old school

 

[Txmat]

Great. Your doing a great job and the fact that the FC is not dropping as fast as it was means your wining the battle. Just keep on testing and shocking until you meet the three criteria and then just let the CL drop back to normal. You may have to vacuum to get the dead algae out of the pool. If you find your having to clean your filter too often vacuum to waste. Keep up the good work.

 

[slawton]

It was suggest here: http://www.troublefreepool.com/i-si...and-a-life-outside-fighting-algae-t26333.html that metals could be a problem.

So, I took my water to our local (and only) pool store guy two days ago for testing. He tells me he can't/doesn't even test for metals! He tests my water and finds nothing really out of whack.

I begin to explain to him about this site, how people here manage their pools, etc. and he just laughed it off...He said the ONLY way I could have a metals issue is if I put well water into the pool, which I did not.

He didn't even think of suggesting the SWG ionizer and I didn't see this post until after I got home or I would have told him!

On a side note, he did test my water and all the numbers looked great. He didn't know what to suggest.

Can metals get destroyed from shocking? I've been shocking for a few days and at first, I saw a lot of greenish dust sitting on the pool floor. I assumed it was algae. I brushed it all off the bottom and the pool became cloudy. Since, I have yet to see clear water, FC hold overnight and less than .5 CC, I have continued to shock. No longer do I see dead algae on the bottom, but the pool remains cloudy still this morning and I dropped from FC-30 (shock level) to 25.5. Shocked it again.

The reason I ask about the metals is because continued shocking has not brought to the floor any more algae so I am beginning to wonder if it could be metals.

Can I add the metals sequesterant while shocking or will that royally mess things up? Or, does shocking not necessarily bring dead algae to the bottom? I also have noticed my Slimebag (see this post:http://www.troublefreepool.com/is-it-dead-was-slimebag-sadness-t25493.html) and filter sock don't have that greenish tint anymore and don't seem to be collecting the green stuff like they were. Still, the water is cloudy, but more of a white cloudy....

 

[Txmat]

I will let the more knowledgeable post about metals. I will say that I am not suprised about the pool store guy. I have really only found one guy (he owns a small independent) at a pool store that really knows what he is doing and talking about. And he will bad mouth BBB and sites like this because he makes his money on chemicals.

As to your pool. I think you are still killing organics. Your overnight drop of 4.5 would indicate your still in the killing process and hence need to continue shocking. I do not believe metals eat chlorine. Have you tried vacuuming the pool bottom recently? You might have more dead stuff down there than you think. I have found vacuuming to waste gets me a noticeable difference in the clarity of the water. The fact that your not seeing green indicates to me that you are almost there. The fact that your pool did not pass the overnight test indicates to me you are not there yet.

 

[slawton]

Another drop of 5 this morning....the pool does not yet look "sparkling" but has kind of a white cloudiness to the water. The greenish color has gone away for sure.

Txmat, I tried the suggestion you had about the 30 minute thing and is pretty dead on. After adding my bleach this morning, I tested after only 30 minutes and the FC went from 25 to 29 (the pool calculator said it would be at 30). I thought that was pretty accurate, so I felt better about that.