Help with Numbers!!!

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oasis1

0
LifeTime Supporter
Apr 18, 2010
221
Central Illinois
Hi,
I'm getting ready to close pool next week sometime and for as much bleach (which is ALOT) my numbers don't seem to match.

Tuesday 6:50pm FC 9.5 CC 0 added 121oz. bleach
Wednesday 12:30pm FC 9 CC 0 added 121 oz. bleach
4:15pm FC 10.5 CC 0 added 121 oz. bleach
5:35pm FC 18 CC 0
Thursday FC 8 CC 0 overnight test tonight
Friday 6:00am FC 8 CC 0 added 121 oz. bleach (when I did overnight test I don't think it passed but the number I wrote says it did.....I mustve been sleepy!
9:00am FC 14 CC 0.5
10:30am FC 12.5 CC 0.5 added 121 oz. bleach
2:00pm FC 13 CC 0.5 added 121 oz. bleach
3:50pm FC 15 CC 0.5


FYI the CYA is between 20-30

Could anyone tell me whats going on?
 
What is the volume of your pool? Put that in your signature instead of the dimensions.

Are you trying to SLAM the pool or just maintain it? With the low CYA and the high FC you will be losing a lot of the FC to the sun whether you have algae or not.
 
Volume is about 12500

isn't that a large amount of Bleach that is being used up? Earlier in the season I could add 121 oz. bleach and it would be good for a couple days. I've added 363oz. today!! I wasn't expecting the numbers to drop so much or after I added so much bleach (look at today 10:30 and 2:00)

I'm not sure when pool store coming to close so I want to make sure I have it shocked and ready to go in case they come Monday.
 
What does the water look like?

Each bottle should add about 6.4ppm of FC and that is basically what you got from 6AM to 9AM. Then the sun came out and it started dropping.

The CYA level kind of sets the % of FC you will lose to the sun. The lower the CYA, the more that is lost. And the higher the initial FC level, the more ppm lost for a given %.

So today you have added 6.4*3 = 19.2ppm ... plus the initial 8ppm = 27.2ppm
Lets say by tonight it drops to 13.5ppm ... that means you lost about 50% of the FC today ... which is certainly around the normal range for your low CYA.

If you would have not added any bleach today, assuming your water does not have anything growing, you would likely have only dropped to 3-4ppm ... thus only losing 4-5ppm instead of the 13+ ppm you actually saw.

If you are trying to SLAM the pool, according to the FC/CYA Chart you should be trying to maintain a FC level of around 11ppm and not dosing so high (which could in fact be damaging your vinyl pool).
 
Water is sparkling as it has been since we got the pool, thanks to BBB method!!
is it ok to keep it right around 11 until they close pool even if its not til Friday or should I let it go down to normal range and get it high a day or two before they close?

I'm going to do overnight test tonight
 
If you pass the 3 criteria (you are only now missing the OCLT), then no reason to keep it that high. Just raise it before they come out and keep it above 2ppm until then.

Are you also adding the polyquat?
You do realize we recommend not closing until the water is < 60 degrees right?
 

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