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
Gold Supporter
- Oct 4, 2020
- 1,615
- Pool Size
- 30000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60 Plus
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.