CYA added per 3" tablet of trichlor - the answer?

[aquarium]

I talked to a tech support person at one of the big chemical companies and he said the following:

Trichlor tablets are about 54% CYA.

One pound of anything dissolved in 10,000 gallons of water will yield 12ppm.

Therefore, one pound of trichlor in 10,000 gallons adds about 6.5ppm CYA.

Each 3" puck weights 8 ounces, so if you use two a week that's adding 6.5ppm per week per 10,000 gallons.

Soooo...

If I have a 15,000 gallon pool and add two pucks per week, that's (10/15)*6.5 = 4.3ppm

Is that right?

TW

[bdavis]

Edit

Close

Darn! Good catch. You are correct.

Color me stupid, guess I was thinking something else.

Carry on!

Cheers

[Rangeball]

What is the % of available chlorine stated on the bucket of tabs you have? Does it correlate with the CYA % so that together they equal 100%?

Just curious, cause if it does it would seem you could subtract the chlorine % from 100 and get the CYA total for other manufacturers pucks and sticks. EDIT- nevermind, I just checked, was thinking something else when I posted this. The label on my sticks says "90% available chlorine" and 99% trichlor...

I used to use 8 oz trichlor sticks from Blue Wave. I have 12 left. I had been contemplating adding them to my pool to get the CYA up. If I use the % you listed above, each stick would have 4.32 oz of CYA. Using the bleach calc, to raise CYA in my pool by 10 ppm (21,200 gal) I would need 27 oz or 6.25 sticks. Not very many, and I can easily see why I had so many CYA problems in the past and didn't even know it.

I've decided against adding more CYA, as I have about 10-20 right now, and my FC is holding good and staying lower on CL keeps me in line with the capabilities of my OTO test kit

[aquarium]

Yep, I'm running 10-20ppm CYA as well, for the same reasons. But I like my auto-chlorinator and wanted to be able to calculate about when I needed to drain and dilute, rather than use the clunky turbidity test which doesn't go lower than 20ppm anyway. At this rate, it ain't long!

[mwsmith2]

Hm. Ok, 8 oz * 54% = 4.32 oz of CYA. 4.32 oz of CYA in a 15k/gal pool = 2.25 ppm increase. Two pucks/week = 4.5 ppm increase/wk.

For the "standard" 10k/gal pool, one puck with similar chemical composition will give you a 3.4 ppm increase/wk. You can see how people burning through 4 pucks/week can really get high CYA levels.

Michael

[aquarium]

Okay, I'm convinced.

It's mostly bleach for me now too. I think I'll set my auto-chlorinator real low to trickle in some CYA and keep an eye on the numbers.

BTW, the Walmart Ultra-Bleach doesn't come with any analysis info on the label. Since it says "Ultra" is it safe to assume that it's 6%?

TW

[Theusla]

I just bought 10 bottles of Wal-Mart Ultra. It says 6% on the label. It is just hard to find. I don't have one with me or I tell you exactly where it is located.

[Beautye350]

I'm looking at the label of the Walmart ultra bleach right now.

On the back side of the label right under where it says:

"DANGER: CORROSIVE:

It says:

"Contains sodium hypochlorite, 6.00% by weight"



Regards,

Mark

[aquarium]

Doh!

There it is.

Thanks Mark.


TW