My first shock

Apr 25, 2011
23
I am shocking my pool with the method discussed in pool school for the first time ever. I always thought you just dumped in 3 lbs of shock and ran the filter :roll:

My pool was a little cloudy when I took off the winter cover. Nothing major. It's been cloudy ever since I had the liner replaced last July. Not knowing better I just assumed that the company that did the liner replacement balanced my water. The pool fill water itself was a bit of a mess and full of silt and they just dumped a bunch of stuff into my skimmer a few days after the fill. I was out of town when the liner was replaced and pool filled but saw the chemical part. I figured all was good.

You can see the bottom of the pool and the pattern and there's no sign of anything green. The liner itself has a slimy feeling and did ever since it was installed except after I'd vacuum it. I got the PH, CH, CYA, and TA to reasonable levels and started to add chlorine to get to 3 PPM per the pool calculator. I added the bleach and a few hours later tested my water and had a FC level of 0. Hmmm, I expected it to be around 3 ppm. So I did more reading here and saw that I need to shock the pool.

I plugged in the numbers again yesterday to get to a 10 PPM FC level. I added just over 4 gallons of bleach at about 9 AM and tested my water an hour later and it was reading .5 PPM FC with a higher total chlorine reading. I'm thinking maybe it's not mixed it or something. I did brush the pool BTW. Around 11 AM I add another 4 gallons roughly, actually 4.2 gallons. I test the water roughly 90 minutes later and it's reading .5 PPM with a higher total chlorine.

So off to the store I go and pretty much wipe them out of store brand bleach( yes it is 6%). I add another 4 gallons and this time I test the water where I added the bleach right after I put it in and sure enough it's reading 10 PPM. I was starting to wonder if my test strips were any good. Yes, I know they are dodgy and have a test kit due in tommorow.

I test the water 30 minutes latrer and it's reading 10 PPM. I test again and another 30 minutes later and it's down to 5 PPM. So I add 1.5 gallons of bleach and it's back up to 10 PPM. I test an hour or so later and it's down to 5.

Off to Walmart and I wipe out their stock of bleach. I test the water around 7 PM and it's down under under 5 PPM, so another 2.8 gallons go in. I check arounfd 10 PM and it's back down to 5 PPM. So another 2.8 gallons and I'm off to bed.

I wake up and the pool is cloudy as usual and test my FC levels and it's reading 3 PPM. So this is good news I think. Whatever is in my pool is no longer burning through as fast as it first was. I added another 2.8 gallons and need to go test it since it's been about an hour.

I think I'm making progress and I'm finding that shocking requires faith because I can't believe how much bleach I'm going through. I'll keep going and hope I don't need to make another bleach run for a day or so. it's been cloudy and i have around 30 PPM CYA, so the sun isn't making all the chlorine go away. i'm also up in Maine, so it's not like there's a real strong sun beating on my pool right now anyhow.
 
borass,

Good morning!
I think I'm making progress and I'm finding that shocking requires faith because I can't believe how much bleach I'm going through.
That is a very profound statement and should be required reading for every new member on this forum. Well said!
 
You are doing great! Exactly what we recommend - testing and adjusting often because yes, whatever was lurking can consume it as fast as you add it. Brushing is key - especially when you feel a slimy liner - (could be a biofilm). So keep brushing and staying on top of it.

Check local pool stores - sometimes their price on 10-12.5% is actually comparable to store brand bleach, and that means less jugs to haul. I can get 12.5% gallons by me for $2.99 which is a good price.

Keep it up, good job :)
 
Sounds like you have the process down!

The cloudiness occurs when you start winning the battle. The algae turns gray and makes the water cloudy. Keep going until your FC stabilizes as described in pool school.

When I have to shock (which I hope to never have to do again!) I simply can't tote as many bottles as it requires for mine, even with my CYA in check. I have to resort to the 78% Cal-Hypo. Luckily my CH levels allow it.
 
Ok, I just did a test and it read 10 PPM about 1 hour after the last addition. I ran my finger over the liner on the first step and part of it feels clean and part had a little slime. So I brushed the pool again. I'll test my water again in an hour or so.

I have a feeling I'll need to add some DE to my sand filter to clear the water once I've gotten through the overnight test. I'll also probably open up my sand filter and take a peak. It's been a few years since I've opened it. I replaced the 300# of sand in it about 3 years ago I think. What a PITA that was. The filter is in a shed, so if I stick a hose in it to try to flush the sand, it'll just make a huge mess. That's one advantage about having your filter outside I guess.
 
Welcome to TFP :wave:

Post up a full set of test results as soon as your test kit comes in. Before going through the trouble of cleaning the filter, let's make sure you are shocking correctly. 4 gallons of 6% bleach in a 24k gal pool would have only added 10ppm and would have likely been eaten up quickly by organics. The key to following the shocking process is ensuring you are at least at shock level throughout the entire shocking process, if not even a bit higher than suggested by the FC/CYA chart or the poolcalculator.

Sorry if I missed it, but what is your CYA level?
 
The pool calculator shows I should be around 13 PPM for shock if my CYA is 30. Based on the numbers I had this morning I think I'm just over 10 PPM and what i've added. My test strip has been holding steady at 10+ PPM and it's been 2 hours since my last addition. So my chlorine burn rate has slowed alot. I can add another gallon or so to bump it to what should be 13 PPM, but my tests don't go that high.

Any harm in that? I'm pretty sure the additional 1 - 1.4 gallons of 6% bleach won't send my FC to a dangerous level.
 

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A large bleach jug (about 1.4 gallons) will raise FC by a little under 4 ppm in 24,000 gallons. With CYA at 30 I wouldn't raise FC above 19 or 20. If your guess of FC at 13 is anywhere near correct, adding a jug of chlorine will be fine.
 
Thanks, that's what I was thinking.

I was around 3 PPM and added two large jugs, which would put me around 11 - 12 PPM, at 8 AM. 3.5 hours later my test still reads 10 PPM, which is top of the scale. I just added maybe half a jug, which will push me to a max of 15 PPM, unless my assumptions are way off base. In reality it's probably closer to 13 but I will not be adding any more bleach until a test reads under 10 PPM. My next test will be later this afternoon and I'm hoping it still reads above 10 PPM.

My test kit arriving tommorow will let me really determine what all my levels are. What I've done to date isn't perfect but it's put a dent in the organics as far as I can tell.

Wish i had found this site years ago.
 
The test at 3 PM today was 5 PPM, so I added 2.8 gallons, which should have gotten my FC into the area of 13.

Will the water actually clear up? I have two returns pointing to the bottom of the deep end, so nothing is settling out of the water onto the bottom and I doubt my sand filter is pulling much out of the water. My pump has been running 24/7 since Sunday and I don't see much of a change in the cloudiness.
 
Here is a picture from earlier of my deep end to show the cloudiness. It's not terrible in all honesty.


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here is a picture of the stairs, so you have an idea of what the liner should look like. I expect the deep end to be clear like the first step.

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My bleach usage has slowed down quite a bit. I tested last night and it was reading over 10 PPM, so I added nothing. This morning it was reading under 10 PPM, so I added 1/2 a large bottle. It was the remainder from the half bottle I added sometime yesterday. I tested 30 or so minutes later and I was above 10 PPM.

Fedex just dropped off my test kit :party: So now it's time to open it up and do some reading and real testing. Too bad I'm buried in calls today. So i dunno when i'll have a chance to do the tests.
 
Ok, I couldn't wait.

FC 11.5
CC 0
TC 11.5
PH 7.8
TA 150
CH 350
CYA 40
Temp 50 brrr

So my TA and CH are both higher then I expected. No biggie I don't think. I need to look at my CYA to get my shock levels. Time to plug all these numbers into the pool calculator.
 

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