Confused with Shocking and when to stop

tmac

Member
May 16, 2009
14
Hi everyone!
I've been shocking for the past two days. I had a small area of green algae growing near the steps. Otherwise water is clean and clear. I brought the FC up to shock level (16) and have been trying to hold it there by adding bleach every few hours... Seems to be pretty difficult to hold the FC up though. Even after a half hour or so, it seems to drop down to about 10.
My most recent test numbers are;
FC=10
CC=0
PH =7.4
Alk =120
CYA = 50
So my question is, if my CC is "0", is it OK to stop now or should I continue adding bleach??
I'm planning on taking a reading tonight and then another early in the morning to measure my FC drop, but if the CC is at 0, is it even necessary at this point? Guess I'm confused about how long this can go on. I've used about 18 -96 oz bottles of 6% bleach so far. If the FC still drops again by morning, do I have to keep shocking?
Thanks,
Travis
Pebble tech 16000 gal. in-ground.
PS 233 test kit
 

cheddar85

Well-known member
Feb 18, 2010
271
Houston, TX
Generally, you will be done shocking when you lose less than 1ppm FC overnight and have .5 CC or less. When you get to that point and your water is sparkling with no signs of algae anywhere, you're good to go!
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,051
Houston, Texas
Yes, keep shocking. You need to meet all of the criteria John listed for the shock process to be completed. Brush the areas where you see algae. It is common to have poor water circulation near pool steps. Be sure you pour some of your bleach in that area and stir it with the brush to take care of the algae growth there. To prevent algae from coming back keep the FC at the high end of the normal range for your pool. Never let the FC drop below minimum levels.
 

beaumatt

Well-known member
Jul 9, 2009
92
Shawnee, Kansas
I have found that in my pool, the cracks and crevices around the stairs are a breeding ground, so I get in there with a small brush (even a toothbrush) and scrub that area very good. Also, another hiding spot I found was on the underside of the steps on my ladder, mine was COVERED in algae, if that is your case, I would suggest removing the ladder and scrubbing it outside the pool. One final place I found was on the back sides of my skimmers, the trap door and around the back side of the faceplate. Good luck in your battle, but know in the end you will be victorious!
 

tmac

Member
May 16, 2009
14
Thanks for all the info everyone! Super helpful. Think I'm finally understanding.
Ok, will continue shocking. FC dropped about 3ppm from last night, so I added more bleach this morn to bring back up to 16, and will continue to monitor.
Thanks again.
Travis.
 

cheddar85

Well-known member
Feb 18, 2010
271
Houston, TX
That last little while when you're getting so close can seem to take forever sometimes! But you will get there, just keep at it!
 

tmac

Member
May 16, 2009
14
Thanks again everyone! Finally did it!!! Less than a 1ppm drop last night. The FC is holding great! CC=0.
The pH is up a bit though (7.8). Is that just a false reading because the FC is higher from shocking? Should I adjust now with acid, or wait til my FC drops to *normal* levels ?

This site is sooooo helpful, I can't thank you guys enough. :goodjob:
It's June-gloom here in Westchester Ca right now, but at least the pool will be ready when the sun comes out and the kids want to jump in!
Best-
Travis.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,675
Sebring, Florida
The pH is up a bit though (7.8). Is that just a false reading because the FC is higher from shocking?
Yes. Your pH test will get accurate (lower) when FC drops below 10ppm.
 

poolgirl22

Platinum Supporter
LifeTime Supporter
Apr 14, 2010
595
Stephens City, VA
Hang in there...we should have a friday shocking club meeeting...I'm doing it as we speak...grrrr.....duraleigh knows I'm annoyed!!!

My water is crystal clear and shines like diamonds.
I have no visible algae.
I have no CCs....
There's no debris, nothing to indicate a problem and my chemistry looks fine. I'm brushing nothing.

But my pool is consuming FC faster than I consume :cheers: on a Friday nite and for days I've tested and been losing < = 1 ppm at night. Last night 1.5. Dangit!
It's an uphill battle during daylight hours but I'm staying on top of it every 2-3 until nightfall.

To help others out who may end up with the same situation...The culprits I think...my skimmer had some oily black gunk (sunscreen gunk?) on the underside of the lid..
And my stairs were a little stained where my weighted bottles lie...nothing like I used to have (slimy green stuff)

How about if every time we add bleach, we :cheers: ? :mrgreen: :mrgreen: :mrgreen:
 

poolgirl22

Platinum Supporter
LifeTime Supporter
Apr 14, 2010
595
Stephens City, VA
Sun melter--
I will never confuse Clorox with Coors. I promise.

Speaking of which...it's 310pm...time to test and add...white jug in the pool, silver can to me...
 

tmac

Member
May 16, 2009
14
Funny stuff. I can tell you, I'll never confuse my bleach for my vodka.
:lol:

Pool looks great and all is balanced thanks to you folks and TFP!
Rock on!
Travis.
 

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