Intex SWG startup, confused on adding CYA

[cfclay]

This intex manual says to add 2.6 Lbs of CYA to my size pool. Seems odd, because shouldn't the instructions for that be based on a goal compared to your current level?
I'm at 40 ppm, so adding this would put me at around 70 ppm which is ideal for a salt pool I read.
When do you add the CYA, at the same time as the salt?


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[Texas Splash]

You're correct that your CYA should be at a minimum of 70 for a SWG pool. The level of CYA is required to protect the FC generated by your SWG. If you haven't added salt, then you can do that now. Use the Poolmath calculator to determine how much salt you need to reach the recommended salt level which I'm guessing is somewhere around 3,000 or so, but check your manual to confirm. It might take a day or two to dissolve.

At the same time, ensure you have some bleach in the water to maintain an FC of about 2-3 ppm to keep the water clean and algae-free. You can add the stabilizer at any time using the sock-soaking method to let it start dissolving. Once the stabilizer is all dissolved, check your SWG. If it's not working yet to product FC, treat your pool as a non-SWG on the Chlorine/CYA Chart (link below) and increase the FC accordingly to match on that chart. That's important for FC/CYA balancing. Always refer to that chart.

Once your SWG kicks-in and is making FC, then adjust your FC to the proper level for a SWG pool. Hope that helps. Have a nice weekend.

 

[richierich]

Pat - What's the rationale for having a higher CYA level for a salt pool than a non-salt pool?

 

[Texas Splash]

Pat - What's the rationale for having a higher CYA level for a salt pool than a non-salt pool?

Basically, the SWG adds FC very slowly, so it needs more protection from the sun to maintain adequate FC levels. This in turn allows the SWG to not have to generate as much FC and prolongs its life.

Here's another way is was explained by one of our other Experts describes (JasonLion):

Despite what a great deal of the available literature says, higher CYA levels reduce the total amount of chlorine required to sanitize your pool. Even though a higher CYA level requires a higher FC level, the amount of chlorine you need to add each day to maintain that higher FC level is actually lower than what you would need at a lower CYA and FC level. This happens because CYA protects FC from sunlight, reducing the amount lost to sunlight enough to more than make up for the higher FC levels required.

Since less total chlorine is required at higher CYA levels, the SWG cell doesn't need to run as long each day. Since the cell in a SWG has a lifetime based primarily on how long it is on, a lower daily run time results in longer cell life.

A pH comment from Chem geek:

Also, use of the SWCG tends to have the pH rise so being able to lower its output by losing less chlorine to sunlight due to the higher CYA helps to reduce the rate of such pH rise.

 

[richierich]

Ah ok. Pat another question for you. I saw in one of your posts you maintain your pool at 7PPM. Do you notice any chlorine smell or taste or eye discomfort. Everything I have read (other than on here) says about 3PPM is ideal. I do believe TFP over anything else

 

[Texas Splash]

Do you notice any chlorine smell or taste or eye discomfort. Everything I have read (other than on here) says about 3PPM is ideal.

Not at all. Every TFP pool owner should be referring to the Chlorine/CYA Chart to ensure those two are balanced for their pool type. The CYA provides UV protection and buffering comfort to the pool and swimmers. That chart is absolutely critical.

 

[cfclay]

Not at all. Every TFP pool owner should be referring to the Chlorine/CYA Chart to ensure those two are balanced for their pool type. The CYA provides UV protection and buffering comfort to the pool and swimmers. That chart is absolutely critical.

7ppm? Not for for a SWG pool though is it?


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[Texas Splash]

7ppm? Not for a SWG pool though is it?

No Clay. That's my example to answer Rich's last question. Sorry if that confused you. We got a little off-topic. We'll focus on you and your pool. Your FC will be balanced according to a SWG pool, but only after you've added the correct amount of salt and verified that the SWG is producing FC. That may take a day or two. In the meantime, follow the part of the Chlorine/CYA Chart for a non-SWG and keep the bleach FC level maintained accordingly. Hope that helps and clears it up.