how much CYA will a 50lbs of tri clor add?

[mbar]

I seem to stink at math too Richard Oh well, at least I can cook

[Jakebear]

Richard, indulge me please.

So let's check DH calculations. Using 7 oz pucks in 27038 gallon pool. He figured 15 pucks.

Using your formula, I get 2.789724515 ppm/lb in 27038 gal pool and therefore need 3.5845833333333 pounds of pucks to get a 10ppm increase.

Which means 8.19 pucks.

Don't want to put you in the middle but......................

[chem geek]

The formula is about 3.3 ppm CYA for 8 ounces in 10,000 gallons. So,

3.3 * (7/8) * (10000 / 27038) = 1.07 ppm CYA per 7-ounce puck in 27,038 gallons. The accurate calculation gives 1.08 ppm CYA (the 3.3 was rounded).

I'm not sure what you were looking for.

Richard

[Jakebear]

At 1.07 ppm CYA/7 oz puck it should take ~ 9.3 pucks to raise it 10 ppm. We have put 12 pucks in and have not seen the CYA budge. Tests this AM were:

pH 7.4
FC 3.6
CC 0
TA 90
CYA <30 ppm
Temp 83
All with Taylor 2006 kit

Maybe the CYA was lower than we thought (22) to begin with. I just want to "quit with the pucks already" --- they make a black scum ring around the pool and I didn't have that when the CL Pump was in use.

I sure wish there was a different test for CYA -- I just got off the phone with them --- NOPE --- unless you go electronic colorimeter (Taylor doesn't have) and it is still turbidimetric.

[chem geek]

Though Trichlor is cheaper, a faster and more efficient option for adding CYA is Dichlor. At least it dissolves right away. Anyway, I found that using Trichlor in my own pool took a little more than I expected to get the CYA to rise, but the turbidimetric test is clearly not precise visually and is probably quite prone to error at the lower CYA levels where other turbidity of the water itself would become even more important.

CYA presumably adheres to pipes and pool surfaces, at least somewhat, so some that gets added probably doesn't get measured in the water test.

Richard

[aquarium]

I'm probably wrong here, but I -think- adding 50 pounds of Trichlor will add about 25 pounds of CYA. Then you could just use the dilution table on the back of the container of pure CYA at the store to figure out how that affects your own pool.

[chem geek]

That's pretty darn close. 50 pounds of Trichlor is equivalent to 27.8 pounds of CYA in terms of its CYA content (i.e. these stated amounts both raise the CYA by the same amount) -- 332.8 ppm CYA in 10,000 gallons -- obviously way more than anyone would want.