3rd summer owning a pool. The first year, before I found TFP, was a catastrophe. These past two years have been great. Moved completely to LC and no issues. Since I haven’t used tabs in a couple of years, I try to stay in tune with CYA levels. The weird thing is I measured it a couple of weeks ago using my TF-100 and it was mid 20’s, which seemed legit since I haven’t been adding any. So, I kept my FC between the levels denoted in pool math. I noticed some algae growth and decided to get a 2nd opinion on CYA level so I ran it by the pool store yesterday. They measured it at 48 which is wayyy off. I know it’s a subjective test but are there any tips or best practices for making this more accurate? Normally, I wouldn’t believe the pool store, but with the algae growth, it kinda makes sense. Also, the head scratcher is how do I still have that much CYA in there when I’ve added nothing but LC for the past summer and a half? Help would be appreciated.
Cynauric Acid Levels
- Thread starter Ccross
- Start date
- Jun 22, 2014
- 52,085
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
CYA degrades by about 5-7 ppm per months depending on various pool, swimming, & location condition factors.
This may help you. Always trust your own testing. If you think it was low (20) it probably was which explains the algae. Not enough stabilizer to protect the FC. Algae = SLAM Process
CYA Testing:
Proper lighting is critical for the CYA test, so you want to test for CYA outside on a bright sunny day. Use the mixing bottle to gently mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then gently mix again. Recommend standing outside with your back to the sun and the view tube in the shade of your body at waist level. Then, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. Once it disappears, record the CYA reading. To help the eyes and prevent staring at the dot, some people find it better to pour & view in stages. Pour some solution into the viewing tube, look away, then look back again for the dot. Repeat as necessary until you feel the dot is gone. After the first CYA test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, gently shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate your own CYA reading. Finally, if you still doubt your own reading, have a friend do the test with you and compare results.
This may help you. Always trust your own testing. If you think it was low (20) it probably was which explains the algae. Not enough stabilizer to protect the FC. Algae = SLAM Process
CYA Testing:
Proper lighting is critical for the CYA test, so you want to test for CYA outside on a bright sunny day. Use the mixing bottle to gently mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then gently mix again. Recommend standing outside with your back to the sun and the view tube in the shade of your body at waist level. Then, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. Once it disappears, record the CYA reading. To help the eyes and prevent staring at the dot, some people find it better to pour & view in stages. Pour some solution into the viewing tube, look away, then look back again for the dot. Repeat as necessary until you feel the dot is gone. After the first CYA test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, gently shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate your own CYA reading. Finally, if you still doubt your own reading, have a friend do the test with you and compare results.
20 CYA is too low for your UV exposure down south. The sun burns off your FC and then you're dancing minimum or below.
We round up CYA so technically yours is a 30, but if it's really in the 20s, you need a solid 30. Most need 40 by you for the peak season.
We round up CYA so technically yours is a 30, but if it's really in the 20s, you need a solid 30. Most need 40 by you for the peak season.
Would you ever cheat off the dumbest kid in class ? I don't give a flying rats patootie that he got 3 right last time. Take your best guess with your A+ average. My money is on you, any day of the week.
Thanks for the info, it seems the more I learn the less I know, lol! I’ll retest this evening when I get home and post the outcome! I can keep the chlorine pretty hot but am worried about keeping it too high based off my CYA reading, then find out I was wrong and someone grows a third arm in swimming in 8-10 ppm FC, haha.
No worries. They'd lose the 3rd arm, not grow it. Problem solved !!
Good point. It’s just that all the other test are pretty much black and white, and CYA seems to be subjective. Just worried about getting it wrong and then getting levels too high and causing a chlorine block
No worries at 40. I'm running a 70 way north of you. You could screw it up to 50 or 60 and still be fine. Many in the hot climates go there on purpose and you're kinda on the edge of where it gets nasty hot. The only downside is if you have to SLAM you'll have a higher FC target.
Chlorine lock isn't a thing. You simply need a higher FC level with more CYA. When people have ridiculously high CYA levels, they get into trouble with their normal FC range which wasnt boosted accordingly. Maintaining the level is more or less the same, minus the initial boost. FC burns off as a % and does so quicker when it's higher, but the higher CYA also buffers it more to basically make it a wash.
- Feb 6, 2015
- 7,855
- Pool Size
- 12300
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
There is no such thing as "chlorine lock".
It's a made up pool industry term for when they can't figure out what to do after they sold those overpriced magic potions that didn't work.
It's a made up pool industry term for when they can't figure out what to do after they sold those overpriced magic potions that didn't work.
With a CYA at 20, your FC should be 2-5ppm, with a SLAM level of 10.
With a CYA at 30, your FC should be 2-6ppm, with a SLAM level of 12
With a CYA at 40, your FC should be 3-7ppm, with a SLAM level of 16
With a CYA at 50, your FC should be 4-8ppm, with a SLAM level of 20
As you are safe swimming in the water (as long as you can see the bottom) at anything up to the SLAM level, if your FC was at 10 right now, you'd still be above the recommended range for CYA 50...but safe to swim in at CYA 20. No one is going to grow extra body parts
When are you measuring the FC level in relation to when you are adding LC ? Is it possible you are measuring that you added enough (post LC addition), rather than measuring to see what to add (pre LC addition) ?
I lose 3-4ppm a day up here in balmy mid-Michigan with 60+ CYA, so I have to believe you are running out of FC pretty quick
With a CYA at 30, your FC should be 2-6ppm, with a SLAM level of 12
With a CYA at 40, your FC should be 3-7ppm, with a SLAM level of 16
With a CYA at 50, your FC should be 4-8ppm, with a SLAM level of 20
As you are safe swimming in the water (as long as you can see the bottom) at anything up to the SLAM level, if your FC was at 10 right now, you'd still be above the recommended range for CYA 50...but safe to swim in at CYA 20. No one is going to grow extra body parts
When are you measuring the FC level in relation to when you are adding LC ? Is it possible you are measuring that you added enough (post LC addition), rather than measuring to see what to add (pre LC addition) ?
I lose 3-4ppm a day up here in balmy mid-Michigan with 60+ CYA, so I have to believe you are running out of FC pretty quick
Note how far off their test of CYA was. Nearly 30 ppm is a big difference.
Whenever you question your testing, the good thing is you can test it again for as many times as you want. I've questioned my CYA test in the past but testing multiple times with similar results re-assures me that what I have tested is correct.
This thread is indicative as to why we should all stay out of the pool store......period
I appreciate that info, makes me feel better. As far as measuring, I typically will measure around seven to 8 o’clock at night just before I add chlorine for the evening. Just a little sidenote, I was diagnosed with bladder cancer in January, and so that is why I was asking about chlorine levels. I know that sounds crazy, but at the doctor stumped if I’m a completely healthy individual thanks for the info, can’t wait to get home and retest. by the way, I seem to have different results if I add it to the to quickly rather than slowly, is that normal?With a CYA at 20, your FC should be 2-5ppm, with a SLAM level of 10.
With a CYA at 30, your FC should be 2-6ppm, with a SLAM level of 12
With a CYA at 40, your FC should be 3-7ppm, with a SLAM level of 16
With a CYA at 50, your FC should be 4-8ppm, with a SLAM level of 20
As you are safe swimming in the water (as long as you can see the bottom) at anything up to the SLAM level, if your FC was at 10 right now, you'd still be above the recommended range for CYA 50...but safe to swim in at CYA 20. No one is going to grow extra body parts
When are you measuring the FC level in relation to when you are adding LC ? Is it possible you are measuring that you added enough (post LC addition), rather than measuring to see what to add (pre LC addition) ?
I lose 3-4ppm a day up here in balmy mid-Michigan with 60+ CYA, so I have to believe you are running out of FC pretty quick
Yes sir, agreed. And I was doing fine until i started questioning myself and had a moment of weakness(stupidity). Thanks
If I do need to raise my CYA, is there a preference of dry stabilizer over liquid. Never added any before.
Liquid clumps up on the bottom and is all but impossible to dose correctly with less than a full jug. And it's spendy. But either CYA added is the same in the end.
We prefer dry acid in a sock(s), hanging carrot on a stick like, in front of a running return. This time of year it'll be mush a half hour later and squeeze out in a couple minutes at that point.
We prefer dry acid in a sock(s), hanging carrot on a stick like, in front of a running return. This time of year it'll be mush a half hour later and squeeze out in a couple minutes at that point.
Liquid is expensive and if you don’t use the whole container in a short period of time, turns into a solid block (yeah, I’ve been there). Dry is cheaper, just takes some time to dissolve using sock method. I usually hang sock for a day then get in and swim around, squishing it to help it dissolve.
So, at 60 CYA, you keep your FC between 5 and 9 pretty much all the time?With a CYA at 20, your FC should be 2-5ppm, with a SLAM level of 10.
With a CYA at 30, your FC should be 2-6ppm, with a SLAM level of 12
With a CYA at 40, your FC should be 3-7ppm, with a SLAM level of 16
With a CYA at 50, your FC should be 4-8ppm, with a SLAM level of 20
As you are safe swimming in the water (as long as you can see the bottom) at anything up to the SLAM level, if your FC was at 10 right now, you'd still be above the recommended range for CYA 50...but safe to swim in at CYA 20. No one is going to grow extra body parts
When are you measuring the FC level in relation to when you are adding LC ? Is it possible you are measuring that you added enough (post LC addition), rather than measuring to see what to add (pre LC addition) ?
I lose 3-4ppm a day up here in balmy mid-Michigan with 60+ CYA, so I have to believe you are running out of FC pretty quick