I've read on the forum that when opening a pool and FC is 0 and CYA is 0 that you should wait to add CYA until the FC is holding. Please explain why it's necessary to wait to add CYA. I'm just trying to understand.
CYA 0 When Opening
- Thread starter Lroberts32
- Start date
If all your CYA is gone, it's highly likely that some soil bacteria got into your water and gobbled it all up and pooped out ammonia. It takes a LOT of chlorine to break down the ammonia before you can even start killing off all the little critters that produced it in the first place. It happened to me last year. It took about 12 gallons of 10% to get the FC to hold for more than 15 minutes.
There's a certain bacteria that eats CYA and leaves ammonia behind. Think of it like yeast. Yeast takes sugar and turns it into carbon dioxide. This takes CYA and turns it into ammonia. Adding more CYA will just create more ammonia. It takes approximately ten times as much bleach to neutralize ammonia. So why make a tough job even harder? Kill the bacteria while neutralizing the ammonia by adding bleach. When it stops disappearing almost instantly and turning into combined chloramines, you've finished. Then you can proceed.
Can you post a set of test results including your CC level. I frequently see a large reduction in CYA upon opening from the addition of fresh water from snow and such. Also, how did you cover your pool?
If I were to guess the lowering of CYA is likely from snowfall over the winter. I see it frequently as our cover seldom keeps everything out.
Try this,
Add enough chlorine to reach 10ppm. Then after about 30 minutes test again your FC and CC levels. Let’s see what happens.
Try this,
Add enough chlorine to reach 10ppm. Then after about 30 minutes test again your FC and CC levels. Let’s see what happens.
Very interesting. I recently added 5 lbs of conditioner which should have raised my CYA to 75 to 80. Within 7 to 10 days it has gone back down to 50. I just added half the new required amount. My CCs are < 0.5, phosphates zero and the pool is clear. Are you suggesting I slam or attempt something less than that? Right now my SWCG ( a Jandy Apure 35) has completely stopped working. So I am manually dosing chlorine to a FC 6 target.
borjis
LifeTime Supporter
When cya is consumed this way sometimes it does not complete and then you gotta get rid of the ammonia.
A low cost aquarium test from a pet store can show if you have ammonia.
That ammonia conversion process, a lot of times ends up completing itself where the ammonia turns to nitrogen, which is harmless.
From the stories read on the forum it seems like it is rare to end up with ammonia.
A low cost aquarium test from a pet store can show if you have ammonia.
That ammonia conversion process, a lot of times ends up completing itself where the ammonia turns to nitrogen, which is harmless.
From the stories read on the forum it seems like it is rare to end up with ammonia.
That was a good post and a good explanation of ammonia but I would take exception to CYA/ammonia process in pool water being commonplace. Anecdotal evidence here on the forum would put the frequency at less than 10% and I think it is actually FAR less than 10%. Nevertheless, it DOES exist but I think we make too big of a deal about the issue.
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