3" Tablet cya math problem.

[tcat]

I've been using Clorox for a couple years now. Had a lot of rain last night and had to drain some water. I forgot to switch the valve from waste to filter, pump was off, I went to work... wife called "pool is 25% empty".. I had forgotten my timer went on an hour after I left. Anyway, my cya is about 10 (maybe). I plan on using 3" pucks in the automatic dispenser to get cya up. How long will I need to run it on "5" in a 15k pool to get cya up to 40?

Also, with cya between zero and 20, does that mean I need almost no chlorine to prevent algae?

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[Casey]

If you were going to run a low CYA level the target would be 3ppm FC but it would all burn off in that hot Texas sun!

I don't really mess with pucks. Haven't touched one since 2006. I use the CYA and the sock and I'm done. No worries on how many pucks can do this in this amount of time and having to play with the pH because it's low due to the puck... :blah: :blah: :blah: Did I mention I hate math? I do!!!

 

[jblizzle]

Just use PoolMath to see how much CYA each tablet adds and only put that many the feeder. A setting of 5 is meaningless because flow rates vary for each pool.

 

[Durk]

Pools worked just fine before CYA was invented. I would suggest running your filter starting at sundown thus allowing maximum FC build-up before the sun hits. Algae won't be an issue if you hit 3ppm by dawn. I have never used a sock in my life (in my pool!). I just run pucks while the water is cold until CYA is where I want it. It is almost always cheaper to run pucks IF YOU NEED THE CYA--and then switch to LC when CYA is where you want it. You should just know for future reference how much one of your pucks will raise CYA in your pool. In my 28k pool, one of my 7 oz. pucks raises CYA by ~1 ppm. So you will get roughly 2 ppm per puck as a rough number. So just load her up full, let her rip on max and see where your levels come out. Confirm that your FC matches your CYA as it builds and all will be fine.http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock Run through a dozen pucks, switch to LC for a week, check your levels, then adjust as appropriate.

Someone will suggest FC levels may be low at the end of a sunny day for control of bacteria and biological nasties. Personally, 20 years of pool experience before CYA was ever used in pools leaves me unconcerned on this point. We went to FC zero every day and survived. But the popular wisdom here says otherwise.

 

[tcat]

Pools worked just fine before CYA was invented. I would suggest running your filter starting at sundown thus allowing maximum FC build-up before the sun hits. Algae won't be an issue if you hit 3ppm by dawn. I have never used a sock in my life (in my pool!). I just run pucks while the water is cold until CYA is where I want it. It is almost always cheaper to run pucks IF YOU NEED THE CYA--and then switch to LC when CYA is where you want it. You should just know for future reference how much one of your pucks will raise CYA in your pool. In my 28k pool, one of my 7 oz. pucks raises CYA by ~1 ppm. So you will get roughly 2 ppm per puck as a rough number. So just load her up full, let her rip on max and see where your levels come out. Confirm that your FC matches your CYA as it builds and all will be fine.http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock Run through a dozen pucks, switch to LC for a week, check your levels, then adjust as appropriate.

Someone will suggest FC levels may be low at the end of a sunny day for control of bacteria and biological nasties. Personally, 20 years of pool experience before CYA was ever used in pools leaves me unconcerned on this point. We went to FC zero every day and survived. But the popular wisdom here says otherwise.

Thank you! Added 8 pucks, will see how things look in a week. I turned off my Clorox drip, just needed a ballpark on how long it takes for pucks to dissolve.

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[anonapersona]

Do test TA because the pucks will reduce it. You just added tap water so consider where the pool was and what you tap water TA is. My rule of thumb is that pucks change TA by about the same amount as FC. Use Pool Math or the Pool Calculator to find those values for your pool.

 

[Patrick_B]

A good rough number is for each 10 PPM of FC, you will get about 9 PPM Cya out of the pucks.

Generally, it is too slow a process and can lower your pH more than desired to get where you want to be with Cya.

 

[tcat]

Why too slow? Think I'll be at about 30 in a couple weeks. Have bunch of 3" pucks from previous owner. My pH never seems to get below 7.8, so lowering pH is a good thing. My TA started at 100, would like to get it down to 70. Current: FC 2, TA 85, CYA 20 (maybe)... just ran out of R-0013... to the pool store for the first time this year.

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