Question about shock--0.25 chloramines

[central nj]

Hi,
I've been mostly following these great techniques and this website for 1 year. I haven't shocked my pool since following the methods, and i'm getting a bit nervous. Last year, perhaps every other chlorine test, there was a flash of red using the dpd taylor test kit (the test for chloramines i believe). This year, there is consistently a tiny bit of red when i add the three drops, that always clears with one drop of titrant. When would i want to shock? Thanks. Steve

 

[jblizzle]

That sounds like you would be in the 0.5ppm for CC range , which is not necessarily bad. Although you are noting that this is different than previous ... which is great and shows you are watching your pool.

To check if you need to shock the pool, you can always do an OCLT which would show if something is hiding in the pool.

 

[JasonLion]

CC levels up to one drop of titrant are fine, just ignore them.

 

[bobodaclown]

Are you doing the 10ml or 25ml measurement? The 10ml measurement, .5ppm accuracy rate is exact enough for pool care. You'll save on regents.
Hope that info helps.
Bob

 

[central nj]

Thank you for the help. I was/ am using the 10ml measurement, and mistyped above, and use 5 drops of the reagent to detect chloramines.
Can I ask when i should shock? Chloramines at 1.0? 1.5?

Thanks Steve

 

[Richard320]

Thank you for the help. I was/ am using the 10ml measurement, and mistyped above, and use 5 drops of the reagent to detect chloramines.
Can I ask when i should shock? Chloramines at 1.0? 1.5?

Thanks Steve

The general rule of thumb is over 1.

That being said, it depends. A lot of municipal water systems use chloramines. So if you just added a bunch of water, they'll read high for a day or so until the sun takes care of it. I've gone weeks - no, months - with either zero or .5 CC. Then all the sudden, 1.5! Guess what, the day before my wife had some friends over, so there was quite a bather load. I added an extra quart of chlorine when I dosed it, and CC was back to normal the next day.

Relax and enjoy.

 

[jblizzle]

I have to ask. How do you define "shock"?

You should follow the shock process if:
-CC of 1ppm or higher (sometimes ... see Richard's post)
-visible algae / cloudy water
-Failing OCLT if you think your FC demand is high

You can always bump up the FC a bit before and/or after high usage to help clear the pool, but there is no need to "shock" a pool a given time intervals.

If you maintain your FC correctly, you may never have to go through the shock process.