Shocking, testing but CC stays at 1

lapzanpool

Member
Jul 8, 2010
18
Western MA
I've been shocking my pool to try to maintain an FC of 30 until my CC goes below .5 or the water becomes clear. The day before yesterday I added liquid chlorine to get the FC to 30 ppm. Added it about 8 AM. Tested the water at about 8 PM and the FC only dropped to 22 and the pool was in direct sun most of the day. Does that make sense to have only dropped that little?

Also, my CC is stuck at 1 ppm. Has not budged.

My numbers:

CYA 37
TA 130
CH 180
FC 22
PH 7.6

I know I need to bump the CH (I have a pebble tec pool). Does it matter when I do this, relative to when I'm adding bleach?
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,880
Silver Spring, MD
How are you testing? None of the better test kits give CYA results as precise as "37", they usually go by 10s. To have lost that little chlorine during the day your CYA level must be higher than what the test results say, or the amount of chlorine you added actually raised the FC level significantly higher than 30.
 

257WbyMag

TFP Expert
LifeTime Supporter
Feb 23, 2008
5,061
Denton, TX
The amount of chlorine that you lose during the day isn't really much of an indicator here. Varying amounts can be lost due to sunlight. There isn't a set number.

If you are having trouble clearing things, I would encourage you to brush more often and be sure that you are running the filter 24/7 during this process. When checking for FC loss, you look at overnight loss. Check the FC at sunset and then once again before sunrise. A loss of greater than 1 ppm (or more than 0.5 CC) means you still have some work to do.
 

tim_pool_newbie

Bronze Supporter
LifeTime Supporter
Oct 6, 2009
164
I'm a new pool owner as well as being new to the BBB method, so maybe someone can help educate me as well. But I'm confused why you'd be trying to get your FC shock level to 30. Based on your CYA level of 37, according to the CYA/Chlorine chart posted in Pool School your Shock FC level only needs to go to about 12. And a normal FC level would be around 4. So why are you trying to reach such high numbers?

Again, I'm new to this as well, so maybe I'm not understanding something.

As for when to add chemicals to raise your CH, I recently had to raise both TA and CH and the pool store instructed me (as did most of the posts I've seen online here) to wait at least 24 hours between adding each of the two different chemicals. I'm not so sure bleach gets in the way, especially since you tend to add that every day or so, but you definitely don't want to be adjusting things like TA and CH together.
 

lapzanpool

Member
Jul 8, 2010
18
Western MA
I got the FC 30 from the Taylor book. I've had the pool for 10 years but this is the worst trouble I've ever had getting it clean. This is the latest I've ever opened it so the algae had plenty of time to take hold and it wasn't covered. I decided to give TFP a try because I'm not always confident that the pool techs at the local stores know what they are talking about.
 

benavidescj

LifeTime Supporter
Apr 27, 2010
431
Fleming Island, FL
Yea, as Tim is pointing out 30 ppm is pretty high and not necessary for your pool chemistry. The Taylor booklet is using a generic value for shocking. If you follow the instructions for shocking in pool school you will be using a shock level that is specific to your pool chemistry and save on chlorine costs.
 

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