I'm reading that 1lb of Trichlor (two 3" tabs) added to a 20,000 gallon pool, increases CYA by 3.5 ppm. This begs the question, why add CYA to a freshly filled pool (0 CYA) when the CYA level will increase anyway just by adding 2 or 3 tabs a week for a few weeks? In other words to ramp up the CYA in a fresh pool, use Trichlor tabs rather than plain CYA?
Why add CYA explicitly?
- Thread starter Sherlock
- Start date
borjis
LifeTime Supporter
When i open I need the cya raised immediately so my chlorine doesn't burn up in sunlight from the UV. this can happen as quickly as 15 minutes.
I lose my cya over the winter.
I can dissolve a sock full in about 20 minutes. About 2 hours later my cya is exactly where it needs to be.
Nothing wrong with using pucks, as long as you don't allow the cya to get too high.
I lose my cya over the winter.
I can dissolve a sock full in about 20 minutes. About 2 hours later my cya is exactly where it needs to be.
Nothing wrong with using pucks, as long as you don't allow the cya to get too high.
reggiehammond
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- Oct 4, 2020
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Without any CYA, FC is almost immediately consumed by UV. So it's wise to have at least a baseline of CYA.
If you were to do as you explain, your FC would be under minimum very often, likely leading to algae.
Tabs are not inherently a problem if you manage CYA; for instance, use during vacation, etc.
If you were to do as you explain, your FC would be under minimum very often, likely leading to algae.
Tabs are not inherently a problem if you manage CYA; for instance, use during vacation, etc.
I get this line of thought. I often use dichlor when I need quick CYA, or trichlor when CYA is just a little low.
But here's something to remember: when CYA is too low then you lose a lot of FC to sunlight during the day. Tabs might not be able to keep up depending on how you are dissolving them. And both trichlor or dichlor are acidic. When using trichlor exclusively then it's typically required that the TA is kept around 100-120 to maintain a relatively consistent pH. So then you reach your CYA level and cut the pucks, now you have to deal with regularly rising pH until you add enough acid to drop the TA level. This often takes weeks of daily or semi-daily acid additions.
If CYA is zero then it's a lot easier to bring it up to at least 30 ppm with granular CYA and then using stabilized chlorine to adjust CYA or add chlorine while away, as needed. That's not even getting in to the comfort aspect, where if the trichlor introduces 5 ppm chlorine but 2.5 ppm CYA the water is going to be somewhat unpleasant with a stereotypical chlorine pool smell.
But here's something to remember: when CYA is too low then you lose a lot of FC to sunlight during the day. Tabs might not be able to keep up depending on how you are dissolving them. And both trichlor or dichlor are acidic. When using trichlor exclusively then it's typically required that the TA is kept around 100-120 to maintain a relatively consistent pH. So then you reach your CYA level and cut the pucks, now you have to deal with regularly rising pH until you add enough acid to drop the TA level. This often takes weeks of daily or semi-daily acid additions.
If CYA is zero then it's a lot easier to bring it up to at least 30 ppm with granular CYA and then using stabilized chlorine to adjust CYA or add chlorine while away, as needed. That's not even getting in to the comfort aspect, where if the trichlor introduces 5 ppm chlorine but 2.5 ppm CYA the water is going to be somewhat unpleasant with a stereotypical chlorine pool smell.
Well here's what I did I refilled pool as you might recall and settled upon using just test strips (I did use a proper chemical test kit but found that that was subjective too and decided that for my purposes of making pool generally good, strips are fine).
I added no CYA, of course the level was zero.
I used three tablet floaters and put two tablets in each. Initially each morning the free chlorine was very low, I added a gallon of liquid over the course of each day, made that a daily routine. Naturally the free chlorine would rise sharply then slowly drop again during the day.
For at least ten days that was the cycle, but then I could see that the free chlorine was slowly rising each morning so I eased off the tablet floaters and liquid chlorine, the number of tablets was reduced.
Now about three weeks since it was refilled, everything seems stable, I stopped adding liquid chlorine a week or so ago, and now just rely on tablets and keep them loaded reasonably well, I'll eventually remove one of the floaters.
Every morning I check and free chlorine is in the 3 region (it was clearly almost zero when I started this) so I am now relying only on chlorine tablets but the current CYA level is close to zero, so by never adding any of that explicitly I've kept the CYA level lower and thus increased the effectiveness of the tablets and it will now take much longer for the CYA to get to problem levels.
I'm curious how long it will take for the CYA level to eventually reach 30ppm, the level it would have been if I had added it directly at the start. Because the tablets contribute CYA I saw no real need to initially add 30ppm, if I could supply the liquid daily for long enough to get stability.
I added no CYA, of course the level was zero.
I used three tablet floaters and put two tablets in each. Initially each morning the free chlorine was very low, I added a gallon of liquid over the course of each day, made that a daily routine. Naturally the free chlorine would rise sharply then slowly drop again during the day.
For at least ten days that was the cycle, but then I could see that the free chlorine was slowly rising each morning so I eased off the tablet floaters and liquid chlorine, the number of tablets was reduced.
Now about three weeks since it was refilled, everything seems stable, I stopped adding liquid chlorine a week or so ago, and now just rely on tablets and keep them loaded reasonably well, I'll eventually remove one of the floaters.
Every morning I check and free chlorine is in the 3 region (it was clearly almost zero when I started this) so I am now relying only on chlorine tablets but the current CYA level is close to zero, so by never adding any of that explicitly I've kept the CYA level lower and thus increased the effectiveness of the tablets and it will now take much longer for the CYA to get to problem levels.
I'm curious how long it will take for the CYA level to eventually reach 30ppm, the level it would have been if I had added it directly at the start. Because the tablets contribute CYA I saw no real need to initially add 30ppm, if I could supply the liquid daily for long enough to get stability.
Deb04
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- Jul 12, 2008
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If your pool is 20k gallons, about 9 tabs worth. You don’t say whether your initial six tabs, completely dissolved or how many more tabs you added. But you may already be there.
- Feb 6, 2015
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If 1 lb of trichlor (2 tabs) raises your CYA by 3.5 ppm, 10 lbs of trichlor (20 tabs) will raise your CYA by 35 ppm.
Continued use of trichlor will continue to raise your CYA. But if you continue to use test strips, you won't really have an accurate CYA reading as the test strips show a range only. Additionally, the test strips aren't accurate and degrade quickly over time.
Test strips are only a guess - and a poor one at that. Use you test kit - while you may think it's subjective, it will provide consistent results you can actually depend on. Be methodical in your testing. Review the extended test kit directions.
www.troublefreepool.com
Using tabs will allow your CYA to continually climb amd cause a need for higher FC levels to keep the pool sanitary.
Use of tabs is not a sustainable way to manage pool water chemistry.
Fill out your signature with pool, pool equipment (including manufacturers and model numbers) and test kit info.
Continued use of trichlor will continue to raise your CYA. But if you continue to use test strips, you won't really have an accurate CYA reading as the test strips show a range only. Additionally, the test strips aren't accurate and degrade quickly over time.
Test strips are only a guess - and a poor one at that. Use you test kit - while you may think it's subjective, it will provide consistent results you can actually depend on. Be methodical in your testing. Review the extended test kit directions.
Extended Test Kit Directions Archives
www.troublefreepool.com
Using tabs will allow your CYA to continually climb amd cause a need for higher FC levels to keep the pool sanitary.
Use of tabs is not a sustainable way to manage pool water chemistry.
Fill out your signature with pool, pool equipment (including manufacturers and model numbers) and test kit info.