# Thread: Shock Level difference between poolcalculator.com and CYA / Clorine chart

1. ## Shock Level difference between poolcalculator.com and CYA / Clorine chart

Good Morning Everyone,

My SWG pool turned green and I am in the process of slamming the pool. Someone jumped my fence and turned off both my pump and swg (this has happened 2x this summer). I didn't notice this because I had just had some biopsies done and didn't check my pool for 3 days. Everything was programmed and running smoothly all summer long so I didn't worry about checking it while I was in so much pain.

I used this chart to determine my shock level:
Pool School - Chlorine / CYA Chart

It says for a SWG pool with a cya level of 80 I should keep the chlorine level at 31.

When I put all my numbers into the pool calculator online ( poolcalculator.com) it tells me to use " SWG: 4 Normal: 6 to 11 Shock: 21 Mustard Algae Shock: 42"

Should I use the 21 the calculator recommends or continue to use the 31 the chart recommends?

My Current Numbers are as follows:

FC 32
CC 0
PH set to 7.2 before slamming
TA 90
CH
150
CYA 80
Salt 3250

Also, on a side note... I used the pool calc to determine my pool volume and it gave me the total of 11400 but Intex says it holds 10421 at 90% capacity. I have a 22x52 round ABG. Should I use the pool calc volume or Intex?????

2. ## Re: Shock Level difference between poolcalculator.com and CYA / Clorine chart

I would not use poolcalculator.com but PoolMath here on the site.

Pool calculator is unmanaged and unreliable. PoolMath is updated regularly.

3. ## Re: Shock Level difference between poolcalculator.com and CYA / Clorine chart

Originally Posted by Deb_B

Also, on a side note... I used the pool calc to determine my pool volume and it gave me the total of 11400 but Intex says it holds 10421 at 90% capacity. I have a 22x52 round ABG. Should I use the pool calc volume or Intex?????
I would use the Intex quoted volume and see how your chemical additions track with pool math. Even though Intex pools are "round", their sidewall profiles are not exactly straight and most volume calculators will assume a straight sidewall which is not at all accurate.

4. ## Re: Shock Level difference between poolcalculator.com and CYA / Clorine chart

Got it. So i'm staying with the 31 shock level per chem 201 and Intex''s 10421 for pool volume .

I thought that the pool calculator was a tfp website. I've updated my bookmarks to pool math. Thanks!

Deb

5. ## Re: Shock Level difference between poolcalculator.com and CYA / Clorine chart

Originally Posted by Deb_B
Someone jumped my fence and turned off both my pump and swg (this has happened 2x this summer).
Your pool area is a great candidate for a web-accessible camera. Have you considered that? I have several. They're not expensive, they're very easy to configure and they offer great peace of mind. In simple terms, they detect heated motion. Swaying tree branches do nothing, but when the 14 yr old neighbor kid scales your fence to mess with your pump, or when a squirrel falls into your pool, you get an alert on your phone. Some models include not only a mic, but a speaker. The speaker allows to be hours away and still shout "hey, I see you! You're on video! Get out!"

(or in my case, I can be in my office and shout, "hey you #@&%\$ squirrel, stop chewing on my window sill!!!!")

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