CYA zero, TA and CC high - what to do first?

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Justify

Justify

Well-known member
May 7, 2019
74
Iowa
Hello,
I did read and I keep reading the Pool School articles, but I am still not sure what to do and how to do it. Probably will need some crash course for dummies :rolleyes:
My results from last night:
FC 0.5
CC 2.5
TA 180
CYA probably 0 (filled the tube all the way up and the dot was still clearly visible)
pH 7.5

We put CYA pods in both skimmer baskets (from Walmart) and will repeat (I understand it takes about 13 pounds of Cyanuric to get CYA to 70)

Then I also need to lower TA. Muriatic acid and then aerating, right?
We do have slide (which could work as water feature, but how long do I need to aerate? And, can we go into pool when muriatic acid is added? My concern is that we normally keep the pool covered (and obviously can't aerate when covered), but I also don't want to keep it uncovered when no one is in because we have common grackle colony nesting around and still dive bombing our pool.

And then we also will need to SLAM to get the CC under 0.5.

Did I get it right? Do I need to adjust CYA first, then work on lowering TA and last to SLAM when CYA and TA are in desirable ranges?
AND, what about aerating during the TA lowering process?
Thanks in advance!
 
No.

You want some CYA -- roughly 30. So if you haven't loaded up to get to 70 yet, good.
Add just enough acid to get to 7.2 pH Dribble it into the return stream. In 15 minutes it'll be dispersed enough to get in.
Lastly you SLAM Process. That may only take a day. The high CC could be because the pool has been covered for too long. How does the water look otherwise?

TA is not something you need to worry about. Just maintaining pH will bring the TA down over time.

You should test CH, though. Low CH is not a problem for a vinyl pool, but high CH could be. Without testing, you don't know.
 
If you closed with a good CYA level, the CYA might have been converted to ammonia.

If that's the case, the pH and TA will fall as you SLAM due to the hydrogen ions released from the ammonia as the nitrogen is converted into nitrogen gas.
 
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Thanks for the answer.
Water looks crystal clear. We did not test CH last night, but we can do it today. When we opened our pool two months ago, pool store tested our water and CH was very low, that's why we didn't worry about testing it this time.

So I add the amount of muriatic acid according to pool math, right? Do I need to wait for CYA to get to 30 before adding the muriatic, or can/should I work on adjusting CYA and pH at the same time? Only one pound of CYA added last night and it already dissolved, so I probably should add another pound before testing CYA again.
 
JamesW said:
If you closed with a good CYA level, the CYA might have been converted to ammonia.

If that's the case, the pH and TA will fall as you SLAM due to the hydrogen ions released from the ammonia as the nitrogen is converted into nitrogen gas.
Click to expand...
Thanks.
Not sure what the CYA level was when we closed. I know it was 0 (from pool store testing) when we opened.
 
Justify said:
Thanks for the answer.
Water looks crystal clear. We did not test CH last night, but we can do it today. When we opened our pool two months ago, pool store tested our water and CH was very low, that's why we didn't worry about testing it this time.

So I add the amount of muriatic acid according to pool math, right? Do I need to wait for CYA to get to 30 before adding the muriatic, or can/should I work on adjusting CYA and pH at the same time? Only one pound of CYA added last night and it already dissolved, so I probably should add another pound before testing CYA again.
Click to expand...
Wait fifteen minutes between chemicals except CYA, because it dissolves so slowly. You can do them one after another, give it fifteen, and immediately start with the bleach. Up to 30 CYA, SLAM level is 10.
 
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@Richard320 I checked the Chlorine/CYA Chart article in Pool School and for SWGC, the lowest CYA in the chart is 60 and SLAM level (?FC) is 24.
Since we have SWGC (Pentair iChlor Salt Generator in my signature), should I still target for CYA 30?
 
Justify said:
@Richard320 I checked the Chlorine/CYA Chart article in Pool School and for SWGC, the lowest CYA in the chart is 60 and SLAM level (?FC) is 24.
Since we have SWGC (Pentair iChlor Salt Generator in my signature), should I still target for CYA 30?
Click to expand...
Yes, CYA to 30. Then you SLAM at 12 FC. When it's finished you can raise the CYA.

It's in the SLAM Process

SLAMing an outdoor pool is most effective when CYA is around 30 to 40. Below 30 you lose too much chlorine to sunlight. As CYA goes up, SLAMing requires more and more chlorine, which starts to get impractical
Click to expand...
 
I apologize for stepping into a thread :) But...
@Justify With your CC of 2.5.... have you done a FC add dose & check in 15 & 30 min increments, to make sure you aren't battling ammonia? You don't want to add CYA before the FC can hold on it's own for 15min... Otherwise you'll make your fight harder
 

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Use Pool Math to figure out how much FC is 10ppm in your size pool. Add it slowly at a return with liquid chlorine. Mix for 15 minutes and test your FC. Let us know what it is. If you can stop the CYA add for now and remove them, do so. If it is the ammonia-eating bacteria they will convert the CYA to more ammonia and make you need even more chlorine to get past the ammonia....
 
@IceShadow so I click on my Free Chlorine page in Pool Math and fill in SLAM Target FC - 10 right?
It says 2 gallons 1 cup 10% chlorine bleach.
So far I added 3.5 pounds of CYA, should I test for CYA first before I add the bleach?
(I will need to run to Walmart to get some bleach so I might just stop now, test CYA tomorrow and then proceed)
If I find out CYA is higher than yesterday, does I mean I don't need to worry about ammonia?
 
I started over today and before adding anything to the pool, I tested again.
FC - 2
CC - 0.5
TA - 150-160
CH - 150
CYA - 15 = when I filled the tube all the way to the top, the dot finally disappeared (y):coffee:
CL - 2-4 or 3-6
pH - 7.2

So, I probably don't need to SLAM, right?
Still need to add some CYA so I will continue what I started two days ago - adding CYA to skimmers, right? It rose from 0 to 15 after adding 3.5 pounds of CYA in the last 2 days.

and probably need to aerate to raise pH without raising TA - it's hot day so my son and his friends could just go aerate swimming and splashing around. Can they do that with CYA pods in the skimmers?
 
Justify said:
I started over today and before adding anything to the pool, I tested again.
FC - 2
CC - 0.5
TA - 150-160
CH - 150
CYA - 15 = when I filled the tube all the way to the top, the dot finally disappeared (y):coffee:
CL - 2-4 or 3-6
pH - 7.2

So, I probably don't need to SLAM, right?
Still need to add some CYA so I will continue what I started two days ago - adding CYA to skimmers, right? It rose from 0 to 15 after adding 3.5 pounds of CYA in the last 2 days.

and probably need to aerate to raise pH without raising TA - it's hot day so my son and his friends could just go aerate swimming and splashing around. Can they do that with CYA pods in the skimmers?
Click to expand...
Yes, they can. And even if they don't. there's nothing wrong with 7.2 pH. Don't mention the CYA pods in the skimmers and they won't mess with them.
 
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