Should I SLAM?

[mdreese]

Hi everyone, thought pool season would never happen here in north/central Pa. I need to clarify a chemistry point. I opened yesterday and have the filter running. The chem is as follows:

fc .5
cc 1
cya 0
ph 7.5
ta 140
borates 80

I plan on SLAMMING the pool but do I need to add cya first? Will it hold the chlorine if the cya is 0?
Didn't see an answer above to that question. Thanks, Mary

 

[jblizzle]

If the CYA is very low, you will lose a lot of FC to the sun very quickly.
It is usually best to add CYA up to around 30ppm and then SLAM based on that level. After a week, verify the CYA level.

 

[JasonLion]

If the water is clear and the CC goes away as soon as you add chlorine then you may not need to SLAM.

While CYA is zero, until 24 hours after you add CYA, add 2 ppm of chlorine each evening after sunset. That will allow the chlorine to work overnight, instead of being lost to sunlight.

 

[mdreese]

Still figuring out this site so I may have already posted this but how do I figure out 2ppm of chlorine to add? And why until 24 hrs after adding cya?

 

[frustratedpoolmom]

Click on the PoolMath link up towards the top of the page. If you need help figuring how to use the calculator let us know. Question - Your CYA at the end of last season? The fact it's 0 now could be suspect...

 

[mdreese]

Added chlorine last night and took some readings this morning. The FC was 1 and the cc was 8!!! Could that be the cya converted to ammonia and thats what the chlorine is breaking up? btw the pool is clear with little to no debris but maybe some pollen. Water is darn cold - 50 - but so is the air. Anyway looks like I will be SLAMMING

 

[jblizzle]

That doess point to ammonia.

 

[Casey]

Hold off on CYA for a minute and keep SLAM'ing to get the ammonia down.

That was a wicked cold winter huh? :lol: So glad it's over!!!

 

[mdreese]

Ha that was beyond cold!! and it still is cold! No swimming for a while Is that New England I detect...."wicked" Grew up in Massachusetts myself

 

[mdreese]

So I added my first loading dose of chlorine to SLAM at 11. fc was 1 and cc 8. Just tested again 2pm and fc now .5 and cc was 12!! Never had a cc that high. Is that the chlorine burning off the presumed ammonia? Why does cya convert over the winter some years and not others? i am so happy to have people to ask these questions. Pool store people are clueless and no one else to ask so all you smart people ...thank you for your time!

- - - Updated - - -

ps..cloudy and cool here, am few moments of sun but not much so I don't think sun is eating it up

 

[JasonLion]

No one has completely decoded the mystery of CYA vanishing. As best we can tell it involves some soil bacteria that knows how to break down CYA growing in the water, but even that brief outline isn't proven, let alone figuring out all of the details.