How much CYA?

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C

*chris*

0
Mar 30, 2010
31
This weekend my 27' (17k gallon) AGP was setup as a salt system. Saturday I dumped in town water (no chlorine) 340 pounds of salt and 5 pounds of cyanuric acid (mostly dissolved in a bucket of hot water.) Right now my SWG is generating chlorine and the stats are the following from a AquaChek dip strip:

Hardness 100
Total Chlorine 1
Free Chlorine .5-1
pH 7.8
Alkalinity 80
Cyanuric Acid (either 0 or 30-50)

I know the first order of business is to get a better test kit, which I ordered the Taylor 2000 test, but I am wondering why the CYA is so low. Is around 1 pound per 5k gallons the proper dose, or do I need more? It seems like the Aqua Rite manual suggests 10 pounds of CYA for a 17K gallon pool.

Chris
 
Test strips are unreliable for CYA testing purposes. It would be best to run a sample to a pool store that uses the standard turbidimetric CYA test to check the level for you.
 
257WbyMag said:
Test strips are unreliable for CYA testing purposes. It would be best to run a sample to a pool store that uses the standard turbidimetric CYA test to check the level for you.
Click to expand...


Good to know, I will see what the Taylor test kit says that is coming in the mail tomorrow.

Other than getting the chemical levels right, do I need to add anything else to a new pool? Does the new water need to be shocked?

Chris
 
Chris,

You should lower your pH to about 7.5 first.

Please list your pool and equipment specs in your signature.
This will be a big help for those trying to answer your questions.
Go to User Control Panel (upper left under TFP logo, select Profile, then Edit Sig..)

Also, please read recommended levels for SWCG here: pool-school/water_balance_saltwater_generator

We recommend a CYA level of 70 to 80 for SWG pools.
What level are you shooting for?....and how many pounds have you added so far?

Use Jason's Pool Calculator (link in my sig) to help determine the correct amounts of chems to add.

If you have problems, just post back and someone will be around to help.
 
I'm not happy right now, I typed a very nice post and it didn't post!
Lets see, what did I say:

Lower your PH down as advised by Butterfly...

5 lbs would put your CYA level around 35. So assume that's your level and raise your FC accordingly. You should use liquid chlorine to raise it up to 3-4 and allow the SWG to keep it steady. It can take 5-7 days for CYA to fully dissolve and register on tests.

Now, tomorrow night when you get your kit - turn off the SWG before you go to bed, and test the FC level. If the FC is holding overnight, shocking isn't necessary. If the FC doesn't hold- then you'll need to shock.

If the FC holds, go ahead and add another 4-5 lbs of CYA to raise your level into range. If you have to shock, WAIT TO RAISE THE CYA LEVEL until you are done shocking. Use liquid chlorine to shock the pool.
 
frustratedpoolmom said:
It can take 5-7 days for CYA to fully dissolve and register on tests.
Click to expand...

I just wanted to emphasize the above point as I have fallen victim to my own impatience before and ended up with CYA levels over 120. Waste of money and water :x

CYA definitely requires patience.
 
Signature updated.

I have only added 5 pounds of CYA, it sounds like I should lower my PH, add 2-3 more pounds of CYA, make sure I can get the FC up to 3 and let it sit for a week or so? Why won't the SWG be able to produce the chlorine by itself?

What does the "shock" setting do on my SWG?

Chris
 
*chris* said:
I have only added 5 pounds of CYA, it sounds like I should lower my PH, add 2-3 more pounds of CYA, make sure I can get the FC up to 3 and let it sit for a week or so? Why won't the SWG be able to produce the chlorine by itself?
Click to expand...
It can; but it's not fast. The point of the initial bleach dose is to get a reasonable FC level quickly, which the SWG can then maintain.
--paulr
 
*chris* said:
What does the "shock" setting do on my SWG?
Click to expand...
Typically it turns the cell to 100% for 24 hours, and then goes back to the previous setting. As PaulR said, that isn't actually very good for shocking by it's self because it produces chlorine too slowly, but it can be handy for maintaining shock level once you have gotten there manually.
 
*chris* said:
it sounds like I should lower my PH, add 2-3 more pounds of CYA, make sure I can get the FC up to 3 and let it sit for a week or so?
Click to expand...

No.... Don't add more CYA until you confirm the FC is holding, and you should not wait a week or so to do this.

You expect your kit today, correct? Tonight, turn off the SWG, test the FC (which you have raised to 4 or so using liquid chlorine) and record the result. Tomorrow morning, test again BEFORE the sun hits the pool. If you lose more than 1ppm of FC, this means that you need to shock the pool and you should do this BEFORE you raise the CYA any higher than it is right now.

IF THE FC HOLDS, you do not need to shock, and you can go ahead and raise the CYA with another 4 lbs. Retest the CYA in a week or so.

Test your FC daily and make sure it is staying consistent.

Yes, Lower the PH today as instructed.
 

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Interesting results this morning, the CYA was up and the pH is down. Also my FC was 3, so I guess the SWG has enough output to chlorinate the pool? I am running my 2 speed pump on low-speed 24 hours a day.

I will test the water this evening and turn off the SWG and see what the results are in the morning.

Chris
 
My Taylor test kit came tonight and I measured the following results:

FC 3
TC 5
CC 2
pH 7.6
acid demand 2 drops dropped pH to 7.2
TA 70ppm
CH 90ppm
CYA 40ppm

So it looks like I need to increase my TA with 120oz of baking soda and 529 oz of calcium chloride to increase my CH (I think I will test this again).

I am glad to see that the CYA measurement more or less agrees with the 5 pounds of CYA I put in the pool. It looks like 3 more pounds of CYA are required as well.

While the pool is not sparkling clear, I can see the bottom very clearly.

I turned off the SWG and will test everything again tomorrow morning.

Chris
 
It looks like you are going by the default values in the Target column of the Pool Calculator. What you really want to be doing is to go by the recommended levels article at Pool School.

There isn't any need to add CH to an above ground, vinyl liner, pool.

Your TA is fine where it is. There isn't any need to add baking soda.

You want to target a CYA level of 80. When it has been at least a week after you last added stabilizer and FC is holding steady, adjust the CYA level from what ever level you have at that point up to 80.
 
If your CC is 2 this means you need to shock.

Don't raise CYA until the shock process is complete. Read How to Shock your Pool in Pool School - maintain shock level until the FC holds over night (SWG must be off) and the CC is .5 or less.
 
I tested the pool again this morning after leaving the SWG off for 12 hours. I had to dilute the sample in half with tap water. The FC is now 4 and the CC is 0 confirmed by my wife :) pH is still sitting at 7.6 Besides adding more CYA, what are my next steps?

The water is still a bit cloudy, how do I clean that up?

Chris
 
A couple of observations. If your FC is 4 why did you have to dilute the sample? The K-2000 reads up to 5. Second, You diluted with tap water. Does it contain chlorine? Most municipal water does. And finally, You really should have ordered the K-2006 not the K-2000. That's all folks :-D
 
Bama Rambler said:
A couple of observations. If your FC is 4 why did you have to dilute the sample? The K-2000 reads up to 5. Second, You diluted with tap water. Does it contain chlorine? Most municipal water does. And finally, You really should have ordered the K-2006 not the K-2000. That's all folks :-D
Click to expand...

My tapwater does not contain chlorine. I tested both diluted and non-diluted since it seemed that I was near the top of the kit (5ppm) measurement range.

Why should I have ordered the 2006 kit, care to elaborate?

Jason, thanks, I will let it sit and see how it goes. Thanks for the help.

Chris
 

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