Oh also, pool is crystal clear with no green dust when I sweep or anything anymore.
Test results after battling the pool for a month
- Thread starter Jared Thatcher
- Start date
- Apr 10, 2018
- 6,396
- Pool Size
- 18375
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
It's normal to lose a substantial amount of FC during a SLAM to UV. Because FC is at such a high level, a good deal of that FC is not protected by the CYA.
Hopefully you are now using liquid chlorine. Solid forms of chlorine are not recommended during a slam.
.
Hopefully you are now using liquid chlorine. Solid forms of chlorine are not recommended during a slam.
.
Yep using liquid ever since the first one. It’s incredible how much FC the UV rays eat up
- Jun 24, 2021
- 16,401
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Is there a reason you are using granular? Likely you are adding CYA back. I would suspend the use of granular, use liquid chlorine.
I would retest your CYA.
I would retest your CYA.
It was what I had on hand on Saturday. It better not have any CYA in it, since the packaging says it doesn’t.
- Jun 24, 2021
- 16,401
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Then it has calcium. Not a big deal, but you didn't post a calcium number. High calcium can cause scale on the liner and in a SWCG cell if you have one. The only way to lower calcium is to replace water (or RO).
Just so you know...
Hopefully the last update! OCLT was at 18ppm last night at 8pm and at 17ppm this morning! So hopefully that means I am finished with SLAM. So, if I am done, do I let the UV eat the FC down to my recommended level now? Also did another CYA test yesterday and the result was closer to 40 than it was 50. Seems very subjective but at least I know it’s somewhere between 40-50.
- Jun 24, 2021
- 16,401
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Let it drift down. You might slam one more day for insurance.
Your CYA is 50, always round up to next 10.
Your CYA is 50, always round up to next 10.
Update: Pool is beautifully clear and looking great. I let FC drift down to recommended 6ppm at 50ppm CYA. I’ve been keeping FC at 6ppm and it’s basically costing me between 20-36oz of liquid chlorine every day! Is this normal? It seems like a ton of time and money to have to test and add every single day.
That's 2 to 3.5 FC and entirely normal daily, depending on the weather this time of year. It will slooooowly decrease for the rest of the year soon.
Many go with double doses and skip the in between day. Or just dose today like yesterday and skip the test, then confirm you're still dialed in tomorrow.
Ar some point if not already, it's just second nature and it takes longer to huff about it than it dose to test or dose. One of those things you put off for hours but only takes 4 mins when you finally suck it up.
- Jun 24, 2021
- 16,401
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
That is normal, particularly in summer. In the shoulder months, your FC demand will dwindle.
Few recommendations.
- Keep your FC at the top of the range, 8 for 50 CYA. This will protect from a high FC demand day.
- Add chlorine, so that when you test, you are in range. If you have to dose higher than range, so that you are in range when you test, do that.
- Raise your CYA to 60ppm, this will lower your FC demand. When you get good at maintaining FC, you can even raise to 70. You might find at 70, you get a drop in FC demand. (Only downside of 70 is that if you do get algae, slam gets a bit harder).
Thank you all very much for your advice and help. Good call on keeping it in the upper range, I’ll probably do that, even though it seems like the sun will eat up most of that!
- Jun 24, 2021
- 16,401
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
Where you are on the range does not change what the sun uses.
It doesn’t? It seems like if I had 2ppm FC unprotected by CYA that the sun could eat up before hitting the protected FC, then adding more FC would just allow the sun to eat more FC before hitting the protected stuff?
- Jun 24, 2021
- 16,401
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
It does protect chlorone from the sun. And once you have the protection, it will burn off 2 to 4 FC daily based upon the time of the season and the weather pattern of that time.
Chlorine burns off as a %, so technically more burns off at higher FC levels, but near target range the difference is so small you won't notice that you lost 3.2 ppm at 10FC while only 3ppm at 4FC. (Just an example). The loss becomes noticeable in the 20s and anyone who has done a high CYA slam can attest. They might lose their 4 ppm to the sun plus 2 extra from the higher FC, plus whatever is consumed by the algae.
- Jun 24, 2021
- 16,401
- Pool Size
- 29000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
CYA does protect from the SUN.
At any CYA level, the sun will consume the same FC, independent of the FC level (not quite true, at much higher levels of FC, it will burn off faster).
At normal operating levels of FC, the amount of FC consumed is independent of the FC level.
As you raise CYA, FC consumption goes down because the CYA "protects" it.
www.troublefreepool.com
So I should have said:
At any CYA level, the sun will consume the same FC, independent of the FC level (not quite true, at much higher levels of FC, it will burn off faster).
At normal operating levels of FC, the amount of FC consumed is independent of the FC level.
As you raise CYA, FC consumption goes down because the CYA "protects" it.
Pool Water Chemistry
This thread presents my findings so far on pool water chemistry including the following: More Accurate Calcite Saturation Index (CSI) to replace Langelier Saturation Index (LSI) Calculation of ppm HOCl (disinfecting chlorine) at various levels of Total Free Chlorine (FC) and Cyanuric Acid (CYA)...
www.troublefreepool.com
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