Should I start Saturday morning or wait 'till dark to shock?

neato5oh

Active member
Apr 11, 2013
28
If I can get the water circulating correctly (don't ask), I could start dumping chemicals in this morning. It's going to be hot and sunny here. Is it really bad to start during the day? I'd like to have as much time as possible to monitor and adjust before I have to go back to work on Monday. The pool was not opened last year and it is very green. Thanks!
 

BoDarville

TFP Expert
LifeTime Supporter
Jun 5, 2012
3,844
DFW, Texas
Re: Should I start Saturday morning or wait 'till dark to sh

If you have the time to monitor the pool and check FC throughout the day, I would start now and as early in the AM as possible. I'm a little concerned about what you mean by "If I can get the water circulating correctly". The pump should be on 24/7 during the Shock Process. Also, I would lower the pH to around 7.2 before you begin the Shock Process, then ignore it until you are done and FC drops below 10 ppm. I am assuming you know what your CYA is as that will determine your FC target.
 

neato5oh

Active member
Apr 11, 2013
28
Re: Should I start Saturday morning or wait 'till dark to sh

I had some leaks. Just bought the house last summer and just getting to the point of checking things out now.

Roger on the ph. It's 9.5! There were some "ph increaser" granules here. I plan to mix with water and dump in. Have not mesured the cya or other stuff yet but I got the tft test kit so I'll be set. I'm assuming I can deal with the PH before doing the other tests?
 

Richard320

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Jan 6, 2010
23,933
San Dimas, CA (LA County)
Re: Should I start Saturday morning or wait 'till dark to sh

neato5oh said:
I had some leaks. Just bought the house last summer and just getting to the point of checking things out now.

Roger on the ph. It's 9.5! There were some "ph increaser" granules here. I plan to mix with water and dump in. Have not mesured the cya or other stuff yet but I got the tft test kit so I'll be set. I'm assuming I can deal with the PH before doing the other tests?
Is that a typo? What tester reads that high?

And if that's correct, you need pH decreaser aka acid.

But, that said, if pH is corrected and pump is working, start today. It's a lot easier to retest and replenish the chlorine every couple hours while you're up and awake.
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,933
San Dimas, CA (LA County)
Re: Should I start Saturday morning or wait 'till dark to sh

neato5oh said:
yep - typo. It's sodium bisulfate. If I go through that I guess I'll head to home depot for muriatic acid?
Yep. Check the pool aisle first for the good stuff, 31.45%. Sometimes the stuff in paint is "fumeless" or whatever which is a euphemism for diluted.
 

neato5oh

Active member
Apr 11, 2013
28
Re: Should I start Saturday morning or wait 'till dark to sh

Well I dumped about 8 lb's of the "ph decreaser" in and the ph is still 9.5 (testing with the tft kit it's 8.2, but testing with the hatch kit I have for my well water it's 9.5). Does that stuff go bad? Am I missing something?

Wondering how many gallons of muriatic acid it's going to take to get the ph to budge?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,933
San Dimas, CA (LA County)
Re: Should I start Saturday morning or wait 'till dark to sh

neato5oh said:
Well I dumped about 8 lb's of the "ph decreaser" in and the ph is still 9.5 (testing with the tft kit it's 8.2, but testing with the hatch kit I have for my well water it's 9.5). Does that stuff go bad? Am I missing something?

Wondering how many gallons of muriatic acid it's going to take to get the ph to budge?
Sounds right.

PH is logarithmic..9.5 to 8.5 is ten times the jump that 8.5 is to 7.5. So it will take a lot of acid to get things down. Even the pool calculator carries this disclaimer
Results are approximate and can be off significantly for large pH changes.

To get a pool as big as yours from 8.2 to 7.5 will take 2 gallons! I'd just add a gallon at a time and give it an hour circulating between jugs with a little brushing to be sure the dead spots get stirred up until the pH dips below 8.2 somewhere. Then start measuring the doses.

Note that the TA level affects the acid demand, too.
 

neato5oh

Active member
Apr 11, 2013
28
Re: Should I start Saturday morning or wait 'till dark to sh

hmmm... maybe I didn't wait long enough for that other stuff to kick in? I'll recheck after I get back from my acid trip.

Just measured the TA and it is 50.
 

neato5oh

Active member
Apr 11, 2013
28
Re: Should I start Saturday morning or wait 'till dark to sh

... is that a good TA? Should I try to adjust that? I have a bunch of baking soda...

Or should I do the PH first.

BTW - thank you VERY much for your help!
 

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Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,933
San Dimas, CA (LA County)
Re: Should I start Saturday morning or wait 'till dark to sh

neato5oh said:
... is that a good TA? Should I try to adjust that? I have a bunch of baking soda...

Or should I do the PH first.

BTW - thank you VERY much for your help!
I'd save it. You'll probably be losing water when you backwash the filter as you're clearing the green. No point adding TA only to pump it out a few hours later. It's easy to fix once the pool is clear - you have the baking soda already.
 

neato5oh

Active member
Apr 11, 2013
28
Re: Should I start Saturday morning or wait 'till dark to sh

OK - so I dumped in 2 gallons of acid (31.5%) and the PH is now 6.5. Going to try adding baking soda to try to make it go back up.
 
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