Should I shock?

[carlscan26]

Yesterday was a beautiful day. We hosted a BBQ and had up to 7 people in the pool with one being a 1.5 years old; when we took him kut we discovered he had pooped in his swim diaper needless to say everyone came out.

I measured the FC and CC and had 6.5/0. It had been 7/0 a few hours before we started swimming. The pump was running as was the LQ while we were swimming. My FIL who has had pools for 20+ years said if the FC and CC were fine then no need to shock? I listened to him but then tomb safe I did an overnight FC loss test and this morning it read 5/0. So I lost 1.5 ppm FC But the water still looks fine, no sun on it yet but it's crystal clear.

I bumped the FC up to 10 with a bit over 2 qts of CL about 15 mins ago I will remeasure in 15 mins to confirm I got it to 10

Other measurements:
PH 7.8
TA 110
CH 120
CYA 60/70

Thanks!

 

[frustratedpoolmom]

If you lost 1.5 ppm overnight, that's borderline but just to be safe, considering the fecal matter, I'd go ahead and raise it up to shock level this evening, around 7pm or so. Wait a few hours for the bleach to circulate, test the FC around 9 or 10 pm and then again tomorrow morning before the sun hits the pool and then compare.

 

[carlscan26]

Thanks for the fast response! Wouldn't 18 be my shock target?

 

[JasonLion]

CYA of 60 shock is 18-24. CYA of 70 shock is 20-28.

 

[carlscan26]

Ok so it went from 10 to 8.5 in one hour so I raised it to 20 (6 qts). Will remeasure in 30 mins.

Meanwhile I closed the LQ so it doesn't throw things off either - I did that this morning actually.

Edited to correct amount of CL added

 

[carlscan26]

CYA of 60 shock is 18-24. CYA of 70 shock is 20-28.

Thanks Jason. Should I go higher than 20 then? I prob will if it drops much after 30 mins.

 

[carlscan26]

Update: I have had to add 2 qts in each of the last two hours. There's definitely some biologicals in there and the sun to some extent right? I use 1 qt a day usually... Anyway FC is at 23 or should be. Heres hoping it's slowing down or I'm going to have to get more CL - I'm down to 1.5 gals and I started with 4! This is full strength CL btw.

The water looks perfect - clear and sparkly. My daughter. Ant understand why we can't go swimming today

Also I've decided to start working on lowering my TA to 90 since I'm on pool watch anyway. Based in the starting ph of 7.8 I added enough acid to get down to 7.1 (a little buffer for measurement error of the color matching) and I've turned the returns to the surface and turned on the waterfall too. Fun fun.

 

[JasonLion]

Remember that the PH test doesn't work correctly while you are at shock level.

 

[carlscan26]

Remember that the PH test doesn't work correctly while you are at shock level.

I based the acid addition on the pH reading this morning before I started shocking. But yeah I won't be able to measure the pH rise until I'm done shocking. I haven't seen a fast rise with the pH when I just run the waterfall so hopefully I don't over shoot while I'm shocking.

 

[Butterfly]

Comment, FWIW

If I had had your experience w/the party & the accident, I would have shocked my pool ASAP.

It doesn't hurt to shock your pool, you gain peace of mind, and you probably could have avoided missing a day of swimming

Just something to consider. my .02

 

[carlscan26]

Yeah I will in the future if it happens again. I didnt follow my gut on this one.

 

[carlscan26]

Ok so I've been losing 1.5 to 2 ppm for the last three hours. It actually looked like it was slowing down and then jumped back to 2. Going on my 4th gallon of 12.5% CL. I definitely should have hit this last night. Lightening doesn't strike twice right? I got lucky with the dead bird earlier this week but not this one. Oh well.

Edited for spelling and iPhone errors.

 

[carlscan26]

Holding steady at 22 for the last two hours. Over night FC test here we go...

Should I leave the pump running all night? It usually is off from 7-7. But with shocking I believe I should leave it on all night right?

 

[Butterfly]

Most folks shocking are running pumps 24/7.

 

[carlscan26]

Thanks butterfly. By the way your two cents were appreciated.

 

[Butterfly]

Thanks butterfly. By the way your two cents were appreciated.

You're welcome and keep us posted

 

[carlscan26]

Re: Should I shock? - new strategy

So this morning I lost 1.5 ppm overnight so I'm keeping the shocking process going. Howeve due to work I can't baby sit the pool today so I got it up to 22 and turned the LQ back on. I'll measure at lunch if I can find some R-0871 locally - I think I have two test left (hopefully) - testing at >22ppm uses a lot of reagent. I have almost gone through an entire bottle

So hopefully it stays above 20 all day (it should with the LQ on and if the rate of loss is no faster than it was yesterday) and I kill whatever is left today.

 

[carlscan26]

Ok I have no idea what's going on. Went from 22 this morning to 18. Added 1 qt to get me back to 15 and increased the LQ. At 5:00 it's 15. Now at 7:30 it's 15.5. The sun was only on 1/4 of the pool at 5. My cya is 30 tops. Could I be losing that much just to sun exposure? Sun is on the pool from 8 to 5:30ish. Full sun from 9 to 4.

 

[carlscan26]

Just rechecked my goal shock for a CYA of 30 is actually 15. Could my FC drop be so fast because my cya is at 30 whereas I was shocking for 60?

 

[HotShot53]

I'm not an expert (don't even have my own pool installed yet lol), but from what I've gathered reading these forums extensively the past few weeks, the higher your chlorine level, the faster you'll lose it to sunlight. So if you have like 4 times as much chlorine in there as usual, the sun will make you lose it 4 times (or more) as fast....

For my own benefit... as long as nothing was left in the pool, a dirty diaper wouldn't create an algae bloom, would it? So why is there a need to shock? Other than because it grosses people out?